คู่มือครูรายวิชาพื้นฐาน คณิตศาสตร์ ชั้นประถมศึกษาปีที่ 5 เล่มที่ 1

63 แบบฝึกหัดรายวิชาพ้นื ฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษสว่ น

5 5160 + 7 6 5 − 249
4
.ว..ธิ ..ีท...าำ .........5... . .−.. .. .2...49.....=.....5....−... ..2.9..2.....................
.ว..ิธ..ีท...าำ .......5..1..6.0.....+.....47.....=.....15..06.....+.....74..................... ...................................=.....15...××....99.....−.. .. .2.9.2..............
...................................=.....15..06....××...22.....+.....74...××....55....... ...................................=.....4.9.5.....−.. . ..2.9.2...................
...................................=.....1.2.1.0..2...+.....23..50.................. ...................................=.....2.9.3...............................
...................................=.....1.2.4.0..7............................ ...................................=.....2...59..............................
...................................=.....7..2.7..0............................ .ต..อ...บ......2...95..........................................................
.ต..อ...บ.......7..2.7.0........................................................
.........................................................................
.........................................................................

7 8154 − 7281 8 9178 + 9
12
.ว..ธิ ..ที...ำา......8..1.5.4....−.. ..7..2.8.1.....=.....1.1.1.4.7.....−... ..1.2.5.1..5..............
...................................=.....1.1.1.4.7....××...3.3...−... .1.2.5.1.5....××....22.. .ว..ธิ ..ที ...ำา.....9...1.7.8.....+.....1.9.2.....=.....1.1.6.8..9....+.....1.9.2.................
...................................=.....3.4.5.2.1.....−... . .3.4.1.2..0.............. ...................................=.....1.1.6.8..9...××....22....+.....1.9..2...××....33..
...................................=.....44..12............................... ...................................=.....3.3.3.6..8....+.....32..67.................
.ต..อ...บ.......4..1.......................................................... ...................................=.....3.3.6.6..5............................
...................................=.....1..0...3.5.6..........................
42 .ต..อ...บ......1...0..3.5..6.....................................................
.........................................................................
.........................................................................
.........................................................................

| 19สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหัดรายวชิ าพนื้ ฐาน | คณิตศาสตร์ ป.5 16
บทท่ี 1 | เศษสว่ น

แบบฝึกหดั 1.8

พจิ ารณารปู แลว้ เตมิ คาำ ตอบ
1

1 หรือ 264 ของทง้ั หมด
1) จำ�นวนย�งลบ คดิ เป็น ของท้ังหมด

4

3 หรือ 1248 ของท้งั หมด
2) จ�ำ นวนดนิ สอ คิดเปน็ ของทั้งหมด

4

2

2 หรือ 8 ของทงั้ หมด
1) จ�ำ นวนเหรยี ญหนงึ่ บ�ท คิดเปน็ ของท้ังหมด 32

8

2) จ�ำ นวนเหรียญสองบ�ท คิดเป็น 3 ของท้งั หมด หรือ 12 ของทั้งหมด
8 32

3) จ�ำ นวนเหรยี ญห้�บ�ท คิดเปน็ 1 ของทัง้ หมด หรอื 4 ของทง้ั หมด
8 32

4) จำ�นวนเหรียญสิบบ�ท คดิ เปน็ 2 ของท้งั หมด หรือ 8 ของท้ังหมด
8 32

20 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

64 แบบฝกึ หัดรายวชิ าพื้นฐาน | คณติ ศาสตร์ ป.5
บทท่ี 1 | เศษส่วน
เติมตัวเลขแสดงเศษสว่ น หรอื จาำ นวนนบั ใน
1

1) จ�ำ นวนชมพ่ ู คิดเปน็ 5 ของ 40 เท�่ กับ 25 ผล หรอื 25 ของ 40 เท่�กับ 25 ผล
8 40

2) จำ�นวนน้อยหน่� คดิ เปน็ 3 ของ 40 เท่�กับ 15 ผล หรอื 15 ของ 40 เท�่ กบั 15 ผล
8 40

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1) จำ�นวนหนงั สอื ภ�ษ�องั กฤษ คิดเป็น 2 ของ 30 เท่�กับ 10 เลม่ หรือ 1300 ของ 30
6 เท่�กับ 10 เลม่

2) จ�ำ นวนหนงั สอื ภ�ษ�ไทย คิดเปน็ 1 ของ 30 เท�่ กับ 5 เล่ม หรือ 350 ของ 30
6 เท่�กบั 5 เลม่

3) จำ�นวนหนงั สอื ก�ร์ตนู คิดเปน็ 3 ของ 30 เท่�กับ 15 เลม่ หรือ 1305 ของ 30
6 เท่�กับ 15 เลม่

| 21สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หัดรายวิชาพ้ืนฐาน | คณิตศาสตร์ ป.5 16
บทท่ี 1 | เศษส่วน

จัดกลมุ่ พร้อมระบายสีแสดงเศษสว่ น แล้วตอบคาำ ถาม

1

1) 37 ของ 35 เปน็ เท�่ ใด
.....1...5.............................................................................................................................................

2) จ�ำ นวนรปู ทไ่ี มร่ ะบ�ยสี คดิ เปน็ เศษส่วนเท่�ใดของทง้ั หมด และมีกีร่ ูป
......74.....ข..อ...ง..ท..ั้ง..ห...ม..ด.....แ...ล..ะ..ม...ี .2..0....ร..ูป..................................................................................................

2

1) 58 ของ 24 เปน็ เท�่ ใด
.....1...5.............................................................................................................................................

2) จ�ำ นวนรปู ท่ไี ม่ระบ�ยส ี คิดเป็นเศษสว่ นเท่�ใดของทง้ั หมด และมกี ี่รปู
......38......ข...อ..ง..ท...ั้ง.ห...ม...ด....แ...ล..ะ..ม...ี ..9.....ร..ปู .................................................................................................

22 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

65 แบบฝกึ หัดรายวชิ าพ้นื ฐาน | คณติ ศาสตร์ ป.5

บทที่ 1 | เศษสว่ น

แบบฝึกหดั 1.9

แสดงวธิ หี าผลคณู

1 6 × 2 2 3 × 3
7 8

.ว..ิธ..ีท..าำ...............6...×....27......=.....6....7×...2......................... .ว..ิธ..ที...าำ ...............83....×....3.....=.....3...8×....3........................
...................................=.....1.7..2............................. ....................................=.....89...............................
...................................=.....1...57............................. ....................................=.....1...81............................
.ต..อ..บ........1...57........................................................ .ต...อ..บ........1..81........................................................

3 5 × 10 4 20 × 15
8 35
ตัวอย่�ง ตวั อย่�ง

.ว..ธิ ..ีท..ำา.............85....×....1..0.....=.....5....8×...1...0...................... .ว..ธิ ..ที...าำ ..........32..50....×....1..5.....=......2..0..3..×.5..1..5....................

...................................=.....2.4..5............................. ...................................=......6.7.0.............................

...................................=.....6...41............................. ...................................=......8..47.............................

.ต..อ..บ........6...41........................................................ .ต..อ...บ.......8...47........................................................

5 7 × 16 ตวั อย�่ ง 6 18 × 13 ตวั อย่�ง
21 24

.ว..ิธ..ีท..าำ.............7....×...12...16.....=.....7...2.×.1..1...6...................... .ว..ิธ..ที...าำ ..........1...8...×....21..34.....=......1..8..2..×.4..1...3...................

...................................=.....1.3..6............................. ...................................=......3.4.9.............................

...................................=.....5...31............................. ...................................=......9...34............................

.ต..อ..บ........5...31........................................................ .ต..อ...บ.......9...34........................................................

| 23สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หัดรายวชิ าพน้ื ฐาน | คณิตศาสตร์ ป.5 16
บทที่ 1 | เศษส่วน

ตัวอย่�ง

7 19 × 9 8 12 × 12
36 9

.ว..ิธ..ที...าำ ............31...69....×...9.....=......1..9..3.×..6..9...................... .ว..ิธ..ที...ำา...........1..2....×...1.9.2.....=......1..2....9×...1...2...................
...................................=......1.4.9.............................
...................................=......4..43............................. ...................................=......1..6.............................
.ต..อ...บ.......4...34........................................................
.ต...อ..บ........1..6........................................................

........................................................................

9 20 × 3 10 24 × 1
5 48

.ว..ธิ ..ที...ำา............2..0....×....53.....=......2..0..5.×....3...................... .ว..ธิ ..ีท...าำ ..........2...4...×....4.1.8.....=......2..4..4..×.8..1......................
...................................=......21...............................
...................................=......1..2............................. .ต...อ..บ.........1.........................................................

.ต..อ...บ........1..2........................................................ 2

........................................................................ ........................................................................

11 6 × 17 12 6 × 40
51 240

.ว..ธิ ..ที...าำ ..........5.6..1....×...1...7....=......6..5.×.1...1..7...................... .ว..ิธ..ีท...ำา........2...64..0....×...4...0....=......6.2..×4...0.4..0......................

...................................=......2............................... ...................................=......1...............................

.ต..อ...บ........2.......................................................... .ต...อ..บ........1..........................................................

........................................................................ ........................................................................

24 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

66 แบบฝึกหัดรายวชิ าพนื้ ฐาน | คณิตศาสตร์ ป.5

บทที่ 1 | เศษสว่ น

แบบฝกึ หัด 1.10

แสดงวธิ ีหาผลคณู

1 2 × 3 2 3 × 3
7 5 10 10

ว...ธิ ..ีท..าำ..............72....×....35......=.....72....××...53......................... .ว..ิธ..ที ...ำา..........1..3.0...×....1.3.0.....=......1.3.0...×.×...1.3.0....................
...................................=.....3.6..5............................. ...................................=......1..09..0...........................
ต...อ..บ.........6.......................................................... .ต...อ..บ..........9........................................................

35 100

........................................................................ ........................................................................

3 5 × 2 4 3 × 12
7 9 8 15
ตัวอย�่ ง

ว...ธิ ..ีท..าำ..............57....×....92......=.....57....××...92......................... .ว..ธิ..ีท...าำ ............38....×....11..25.....=......83...××....11..25......................
...................................=.....16...30.............................
ต...อ..บ........61..03......................................................... ...................................=......1.3.0.............................

.ต..อ...บ.......1..3.0........................................................

........................................................................ ........................................................................

5 5 × 7 6 6 × 9
14 25 18 10
ตวั อย�่ ง ตวั อย่�ง

.ว..ธิ ..ีท...ำา..........1.5.4....×....2.7.5.....=.....1.5..4...××....2.7.5.................... .ว..ธิ ..ีท...ำา..........1..6.8...×....1.9.0.....=......1.6.8...×.×...1.9..0...................

...................................=.....1.1..0............................. ...................................=......1.3.0.............................

.ต..อ..บ........1.1.0......................................................... .ต..อ...บ.......1..3.0........................................................

........................................................................ ........................................................................

| 25สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหดั รายวชิ าพื้นฐาน | คณิตศาสตร์ ป.5 16
บทที่ 1 | เศษสว่ น

ตวั อย�่ ง

7 9×6 8 56 × 6
30 14 16 21

.ว..ิธ..ีท...าำ ..........3..9.0...×....1.6.4.....=.....3.9..0...××....1.6.4.................... .ว..ิธ..ีท...ำา...........51..66....×...2.6..1....=......15..66....××...2.6..1...................

...................................=.....7..9.0............................. ...................................=......1...............................

.ต..อ...บ........9.......................................................... .ต..อ...บ........1..........................................................
70

........................................................................ ........................................................................

9 8 × 20 10 11 × 15
10 12 33 25

.ว..ิธ..ีท...ำา..........1.8.0....×....21..02.....=.....1.8..0...××....21..02.................... .ว..ธิ ..ที...ำา..........31...31....×...12...55....=......13..31....××...21...55...................
...................................=......51...............................
...................................=......43............................... .ต..อ...บ........15..........................................................
...................................=.....1...13.............................

.ต..อ...บ.......1...13........................................................ ........................................................................

11 12 × 28 12 18 × 10
9 21 5 24

.ว..ิธ..ที ...ำา..........1..9.2...×....22..18.....=.....1..9.2...××....22..18.................... .ว..ิธ..ที...าำ ...........1.5.8....×...21...04....=......1.5.8....××...21...40...................

...................................=.....1..9.6............................. ...................................=......32...............................
...................................=.....1...79............................. ...................................=......1...12............................
.ต..อ...บ.......1...97........................................................ .ต...อ..บ........1...12.......................................................

26 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

67 แบบฝึกหัดรายวชิ าพ้ืนฐาน | คณติ ศาสตร์ ป.5

บทที่ 1 | เศษสว่ น

แบบฝึกหัด 1.11

แสดงวิธีหาผลคูณ

1 6 2 × 3 2 4 × 4 2
5 7

ว...ธิ ..ที ..าำ.............6...52....×...3.....=.....3.5..2...×....3...................... .ว..ิธ..ที ...ำา............4....×...4...27.....=......4...×....3.7.0......................
...................................=......4...7×....3..0......................
...................................=.....3...2...5×....3...................... ...................................=......1..27..0...........................
...................................=.....9.5..6............................. .ต..อ...บ.......1...7...71................=......1..7...17..........................
.ต..อ..บ........1..9...15.................=.....1...9..51...........................

3 1191 × 10 4 2 4 × 5
5
.ว..ธิ ..ที ..ำา.........1..1.9..1...×....1..0.....=.....12...10...×....1..0.................... ตวั อย�่ ง
...................................=.....2...0..1.×.1...1..0....................
...................................=.....2..1.0.1.0........................... .ว..ธิ..ีท...าำ ............2...54....×....5....=......1.5.4....×...5......................
.ต..อ..บ........1..8...1.2.1...............=.....1...8..1..2.1........................
...................................=......1..4...5.×...5......................

...................................=......1..4.............................

.ต..อ...บ.......1...4........................................................

5 261 × 9 ตวั อย่�ง 6 1156 × 12 ตัวอย่�ง
.ว..ธิ ..ที ...าำ ............2...16....×...9.....=.....1.6..3...×....9...................... .ว..ิธ..ีท...ำา........1...1.5.6....×...1...2....=......21..61....×...1...2...................
...................................=.....1...3...6×....9...................... ...................................=......2..1..1..×.6..1..2....................
...................................=.....3.2..9............................. ...................................=......6.4.3.............................
.ต..อ..บ........1..9...21.................=.....1...9..21........................... .ต..อ...บ.......1...5...34................=......1..5...34..........................

| 27สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หัดรายวิชาพื้นฐาน | คณติ ศาสตร์ ป.5 16
บทที่ 1 | เศษสว่ น

7 4 × 3 1 8 2170 × 30 ตวั อย่�ง
8 .ว..ธิ..ที...ำา........2...1.7.0....×...3...0....=.......21..07....×...3...0..................
ตัวอย�่ ง ...................................=......2..7..1..×.0..3...0...................
...................................=......8..1.............................
.ว..ิธ..ีท...ำา............4...×....3...18.....=.....4....×...2..8.5......................
.ต..อ...บ.......8...1........................................................
...................................=.....4....8×...2...5......................

...................................=.....2..2.5.............................

.ต..อ...บ.......1..2...21.................=.....1...2...21..........................

9 16 × 543 ตวั อย�่ ง 10 25 × 2135 ตัวอย่�ง
.ว..ธิ ..ที...ำา..........1..6....×...5...43.....=......1..6...×....2.4.3.................... .ว..ธิ ..ีท...าำ ........2...5...×....2..1.3..5....=......2..5....×...31...35...................
...................................=......1..6...4×....2..3.................... ...................................=......2..5..1..×.5..3...3...................
...................................=......9..2............................. ...................................=......5..5.............................

.ต..อ...บ.......9..2......................................................... .ต..อ...บ.......5...5........................................................

11 2 2 × 8 12 7 × 552
3
.ว..ิธ..ที...าำ ............7....×...5...52.....=......7...×....2.5.7......................
.ว..ธิ ..ที ...าำ ...........2...32.....×...8.....=......83....×...8........................ ...................................=......7...5×....2..7......................
...................................=......1..85...9..........................
...................................=.....8....3×...8......................... .ต...อ..บ........3..7...45................=......3..7...54..........................
...................................=.....6..3.4.............................

.ต..อ...บ.......2..1...13.................=.....2...1...13..........................

28 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

68 แบบฝึกหัดรายวิชาพนื้ ฐาน | คณิตศาสตร์ ป.5
บทท่ี 1 | เศษส่วน
แบบฝกึ หัด 1.12

แสดงวธิ ีหาผลคณู

1 13 × 2 1 2 5 2 × 42
4 7 7 37
ตวั อย่�ง

.ว..ิธ..ที ..าำ..........1.4.3....×...2...71......=.....1.4..3...×....1.7.5...................... .ว..ิธ..ที...าำ ........5...72....×....34...72.....=......3.7.7....×....34..72.....................
...................................=.....1.4..3...××....1.7.5......................
...................................=.....1..2.9.8.5............................. ...................................=......3.7.7...××....34..72......................
...................................=.....6...22...87............................
.ต..อ..บ........6...22..87........................................................ ...................................=......6.................................

.ต..อ...บ.......6.............................................................

..........................................................................

.......................................................................... ..........................................................................

3 1 32 × 1 1 4 2 1 × 1110
4 8

.ว..ิธ..ีท..าำ........1...32.....×...1...41......=......35....×....45......................... .ว..ิธ..ที ...ำา.......2...18....×....1..1.1.0.....=......1.8.7....×....11...10....................
...................................=.....35....××...54........................... ...................................=......1.8.7...××....11..01......................
...................................=......21..25............................... ...................................=......1.8.8..0.7............................
...................................=.....2...1.1..2............................ ...................................=.....2...28...07............................
.ต..อ..บ........2...1.1.2........................................................ .ต..อ...บ.......2...28..07........................................................

.......................................................................... ..........................................................................

| 29สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หัดรายวิชาพน้ื ฐาน | คณติ ศาสตร์ ป.5 16
บทที่ 1 | เศษส่วน

ตัวอย่�ง

5 1152 × 145 6 229 × 1225

.ว..ธิ ..ีท...ำา........1...1.5.2....×...1...45.....=......11..72....×....59...................... .ว..ธิ ..ที...าำ ........2..29....×....1..2.2..5.....=......2.9.0....×....22..75....................
....................................=.....11...72...××....95....................... ....................................=.....2.9..0...××....22..57.....................
....................................=......52..10.............................. ....................................=......1.5.2..............................
....................................=......2...21..01........................... ....................................=.....2...25..............................
.ต..อ...บ.......2...12...01....................................................... .ต..อ...บ.......2...52..........................................................

.......................................................................... ..........................................................................

.......................................................................... ..........................................................................

7 584 × 2181 8 2 7 × 1178
.ว..ธิ ..ีท...ำา........5...84...×....2..1.8..1.....=......4.8.4....×....31..01.................... 10
....................................=.....4..8.4...××....13..10.....................
....................................=.....1...5.............................. .ว..ธิ ..ีท...ำา......2..1..7.0...×....1..1.7..8.....=......21..70....×....12..58....................
....................................=.....12...70...××....21..85.....................
.ต..อ...บ.......1...5.......................................................... ....................................=......1.4.5..............................
....................................=.....3...43..............................
.......................................................................... .ต..อ...บ.......3...43..........................................................

.......................................................................... ..........................................................................

.......................................................................... ..........................................................................

30 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

69 แบบฝกึ หัดรายวชิ าพื้นฐาน | คณิตศาสตร์ ป.5

บทที่ 1 | เศษส่วน

แบบฝกึ หดั 1.13

1 เติมค�ำ ตอบ เพร�ะ 163 × ........1.6..3............ = ........1.................
1) ส่วนกลับของ 163 คอื .........1.6.3...............
2) สว่ นกลับของ 1145 คอื .........11..54............... เพร�ะ 1145 × ........1...4............ = ........1.................
15

3) สว่ นกลับของ 17 คือ ..........1................ เพร�ะ 17 × .........1.............. = ........1.................
17 17

4) ส่วนกลับของ 119 คอื .........1..9............... เพร�ะ 119 × ........1..9............. = ........1.................

5) สว่ นกลับของ 299 คือ .........2.9.9............... เพร�ะ 299 × ........2...9............ = ........1.................
9

6) ส่วนกลบั ของ 253 คอื .........2.5.3............... เพร�ะ 253 × .........5.............. = ........1.................
23

2 เติมตัวเลขแสดงจ�ำ นวนใน

1) 2 × 3 =1 2) 9 × 5 =1
3 2 5 9

1 =1 4) 1 × 9 =1
3) 4 × 9 1

4

5) 7 × 9 =1 1
9 7 6) × 13 = 1

13

7) 12 × 11 =1 8) 21 × 23 =1
11 12 23 21

| 31สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหัดรายวิชาพ้นื ฐาน | คณติ ศาสตร์ ป.5 17
บทท่ี 1 | เศษสว่ น

แบบฝึกหัด 1.14

แสดงวิธหี าผลหาร

1 2 ÷ 5 2 8 ÷ 3
2 7

.ว..ิธ..ที...าำ ...............2...÷....25......=.....2....×....52........................... .ว..ิธ..ที...าำ ...............8...÷....73......=.....8...×.....37...........................
....................................=.....2....5×...2............................ ....................................=.....8...3×....7............................
....................................=......45.................................. ....................................=......5.3.6................................
.ต...อ..บ........4.............................................................. ....................................=.....1...8...32.............................
.ต..อ...บ.......1...8...32.........................................................
5

............................................................................

............................................................................ ............................................................................

3 6 ÷ 6 4 9 ÷ 4
11 3

.ว..ธิ..ีท...ำา............6....÷....1.6.1......=.....6....×....1.6.1......................... .ว..ิธ..ที...ำา...............9...÷....43......=.....9...×.....43...........................
....................................=.....6....6×...1...1......................... ....................................=.....9...4×....3............................
....................................=......2.4.7................................
....................................=.....1...1................................ ....................................=.....6...43................................
.ต..อ...บ.......6....34...........................................................
.ต...อ..บ........1..1............................................................

............................................................................

............................................................................ ............................................................................

32 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

70 แบบฝกึ หัดรายวชิ าพืน้ ฐาน | คณติ ศาสตร์ ป.5

บทที่ 1 | เศษส่วน

ตัวอย�่ ง

5 16 ÷ 8 6 14 ÷ 6
9 5

.ว..ธิ...ีท..ำา............1...6...÷....98......=.....1...6...×.....89........................ .ว..ธิ..ีท...ำา.............1..4...÷.....65.....=.....1..4....×....65.........................
....................................=.....1...6...8×....9......................... ....................................=.....1...4...6×....5.........................
....................................=......3.3.5................................
....................................=.....1...8................................ ....................................=.....1...1...32.............................
.ต...อ..บ........1..1...23.........................................................
.ต...อ..บ........1..8............................................................

............................................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

7 18 ÷ 12 8 15 ÷ 10
16 12

.ว..ธิ...ที ..ำา..........1..8....÷....11..62......=.....1...8...×....11...26...................... .ว..ธิ..ีท...ำา..........1..5....÷....11..20......=.....1..5....×....11...02......................
....................................=.....1...8..1.×.2...1..6....................... ....................................=.....1...5..1.×.0...1..2.......................

....................................=.....2...4................................ ....................................=.....1...8................................

.ต...อ..บ........2..4............................................................ .ต...อ..บ........1..8............................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

| 33สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หดั รายวิชาพื้นฐาน | คณติ ศาสตร์ ป.5 17
บทท่ี 1 | เศษส่วน

แบบฝึกหัด 1.15

แสดงวธิ ีหาผลหาร

1 5 ÷ 4 2 4 ÷ 5
9 3

.ว..ิธ..ีท...ำา..............59....÷.....4.....=.....59.....×....41.......................... .ว...ธิ ..ที ..าำ...............43....÷....5.....=......43....×....15..........................
....................................=.....95....××...14............................ ....................................=.....34....××...15............................
....................................=.....3.5..6................................ ....................................=......1.4.5................................
.ต...อ..บ.........5............................................................. .ต...อ..บ..........4............................................................

36 15

............................................................................ ............................................................................

............................................................................ ............................................................................

3 7 ÷ 7 ตวั อย�่ ง 4 55 ÷ 11 ตัวอย�่ ง
5 22

.ว..ธิ..ที...าำ ..............75....÷.....7.....=.....57.....×....71.......................... .ว...ิธ..ีท..าำ...........25..25....÷....1..1.....=.....52...25....×...1.1..1......................

....................................=.....75....××...17............................ ....................................=.....52...52...××....1.1.1.......................

....................................=.....51................................... ....................................=......2.5.2................................

.ต...อ..บ........1.............................................................. .ต...อ..บ........2.5.2............................................................
5

............................................................................ ............................................................................

............................................................................ ............................................................................

34 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

71 แบบฝึกหัดรายวิชาพน้ื ฐาน | คณิตศาสตร์ ป.5

บทท่ี 1 | เศษสว่ น

ตัวอย�่ ง

5 49 ÷ 14 6 27 ÷ 6
14 15

.ว..ิธ..ที...าำ ...........14..49....÷...1...4.....=.....41...94...×....1.1.4....................... .ว..ธิ...ีท..ำา.............12...57...÷....6.....=.....21...57...×.....16........................
....................................=.....14..49....××....1.1.4....................... ....................................=.....12...75...××....61.........................
....................................=......14.................................. ....................................=.....1..3.0................................
.ต...อ..บ........14.............................................................. .ต...อ..บ........1.3.0............................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

7 18 ÷ 9 8 12 ÷ 10
42 25

.ว..ิธ..ที...ำา.............41..82....÷....9.....=.....14...28....×....19........................ .ว..ิธ...ที ..าำ..........21...52....÷....1..0.....=......21..52....×....1.1.0......................
....................................=.....41..28....××....19......................... ....................................=.....12...52...××...1.1.0........................
....................................=.....2.1..1................................ ....................................=......1..26..5..............................
.ต...อ..บ........2.1.1............................................................ .ต...อ..บ........1...62..5.........................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

| 35สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหัดรายวชิ าพ้นื ฐาน | คณติ ศาสตร์ ป.5 17
บทท่ี 1 | เศษสว่ น

แบบฝกึ หัด 1.16

แสดงวธิ ีหาผลหาร

1 3÷5 2 7 ÷4
53 12 5

.ว..ิธ..ีท...ำา..............35....÷....35......=......53....×....35.......................... .ว...ิธ..ที ..ำา............1..7.2...÷.....45.....=......1.7.2....×....45........................

....................................=.....53....××...35............................ ....................................=.....1..7.2...××....54.........................
....................................=.....2..9.5................................ ....................................=......34..85................................
.ต...อ..บ........2.9.5............................................................ .ต...อ..บ........43..85............................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

3 9÷7 4 8÷9
54 21 16

.ว..ิธ..ีท...ำา..............59....÷....74......=......95....×....74.......................... .ว...ธิ ..ีท..ำา...........2.8.1....÷....1.9.6.....=......2.8.1....×...1.9..6......................

....................................=.....95....××...74............................ ....................................=.....2..8.1...××....1.9.6.......................
....................................=.....33...65................................ ....................................=......11..28..98..............................

....................................=.....1...3.1.5.............................. .ต...อ..บ........11...82..98.........................................................

.ต...อ..บ........1..3.1..5......................................................... ............................................................................

............................................................................ ............................................................................

36 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

72 แบบฝึกหดั รายวิชาพื้นฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษส่วน

ตัวอย่�ง

5 45 ÷ 14 6 35 ÷ 21
30 72 32 24

.ว..ิธ..ที...ำา.........43...50....÷....17..42......=.....34...05...×....17..42....................... .ว..ธิ ..ีท...าำ ...........33..52....÷...22...14.....=.....33...25...×....22..41.......................
....................................=.....43...05...××....71..24....................... ....................................=.....33...52...××....22..41.......................
....................................=.....5..7.4................................ ....................................=......54..................................
....................................=.....7...57................................ ....................................=.....1...14................................
.ต...อ..บ........7...75........................................................... .ต...อ..บ........1...41...........................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

7 13 ÷ 39 8 63 ÷ 77
56 28 102 154

.ว..ิธ..ีท...าำ ...........15..36....÷...23...89.....=.....51...36...×....23..98....................... .ว..ธิ..ที...ำา.......1.6.0.3.2.....÷.....1.7.5.7.4.....=......1.6.0.3.2....×...1.7..5.7.4................

....................................=.....51...36...××....23..98....................... ......................................=......1.6.0.3.2....××...1..7.5.7.4................
....................................=......16.................................. ......................................=......12..17..............................
.ต...อ..บ........16.............................................................. ......................................=......1..1.4..7...........................

............................................................................ .ต...อ..บ........1..1.4..7.........................................................

............................................................................ ............................................................................

............................................................................ ............................................................................

| 37สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหัดรายวชิ าพ้ืนฐาน | คณติ ศาสตร์ ป.5 17
บทท่ี 1 | เศษส่วน

แบบฝกึ หัด 1.17

แสดงวธิ หี าผลหาร

1 183 ÷ 4 2 5 ÷ 3 2
7
.ว..ธิ...ที ..าำ............1...83....÷....4.....=.....1..8.1....÷...4.........................
....................................=.....1..8.1....×....14........................ .ว..ิธ..ที...าำ ............5....÷...3...27......=.....5...÷....2.7..3.........................
....................................=.....1.8..1...××....41......................... ....................................=.....5...×....2.7..3.........................
....................................=.....13...21................................
.ต...อ..บ........1..1............................................................ ....................................=.....5..2.×..3..7............................
....................................=.....32..35.................................
32 ....................................=.....1..21...32..............................
.ต..อ...บ.......1...21..23..........................................................
............................................................................

3 223 ÷ 9 4 36 ÷ 5 2
16 15 5 ตัวอย�่ ง

.ว..ิธ..ีท...าำ .........2...23....÷....1.9..6.....=......83....÷...1.9..6........................ .ว..ธิ..ที...าำ ..........31..56....÷...5...52......=.....13..56....÷....2.5.7.......................

....................................=.....38....×....1.9.6......................... ....................................=.....31..65....×....2.5.7.......................

....................................=.....38....××...1.9..6......................... ....................................=.....13..56....××...2..5.7.......................
....................................=.....1..2.2.7.8..............................
....................................=.....94...................................

....................................=.....4...22..07.............................. .ต..อ...บ........49..............................................................

.ต...อ..บ........4..22..70.......................................................... ............................................................................

38 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

73 แบบฝึกหัดรายวิชาพนื้ ฐาน | คณิตศาสตร์ ป.5

บทที่ 1 | เศษส่วน

ตวั อย่�ง

5 5 1 ÷ 3116 6 5 5 ÷ 8 1
4 8 3

.ว..ธิ ..ีท...ำา.......5...41....÷....3..1.1..6.....=.....2.4.1....÷....14..69....................... .ว..ิธ..ที...ำา.........5...85....÷...8...31......=.....4.8.5....÷....2.3.5.......................
....................................=.....2.4..1...×....14..96....................... ....................................=.....4.8.5....×....2.3.5.......................
....................................=.....2.4.1....××...4.1..96.......................
....................................=.....1.7..2................................ ....................................=.....4.8.5...×.×..2...53........................
....................................=.....1...75................................ ....................................=.....24..70.................................
.ต...อ..บ.......1...57............................................................ .ต..อ...บ........42..07............................................................

............................................................................

............................................................................ ............................................................................

7 8 3 ÷ 4 1 8 3 1 ÷ 2 4
4 6 9 5

.ว..ิธ..ที...ำา.........8...34....÷...4...61......=.....3.4.5....÷....2.6.5....................... .ว..ธิ..ีท...าำ .........3...91....÷...2...45......=.....2.9.8....÷....1.5.4.......................
....................................=.....3.4..5...×....2.6.5....................... ....................................=.....2.9.8....×....1.5.4.......................
....................................=.....3.4.5....××...2..6.5....................... ....................................=.....2.9.8....××...1..5.4.......................
....................................=.....21...01................................ ....................................=.....1.9.0.................................
....................................=.....2...1.1.0.............................. ....................................=.....1...19................................
.ต...อ..บ.......2...1.1.0.......................................................... .ต..อ...บ.......1...91............................................................

............................................................................ ............................................................................

| 39สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หดั รายวิชาพื้นฐาน | คณิตศาสตร์ ป.5 17
บทท่ี 1 | เศษสว่ น

แบบฝึกหดั 1.18

1 เติม > < หรือ = ใน

1) 2 ÷ 4 = 3 ÷ 4 2) 2 ÷ 1 > 2 ÷ 2
4 8 6 8 5 2 5 3

3) 5 ÷ 5 < 6 ÷ 5 4) 3 ÷ 7 < 3 ÷ 3
6 6 7 3 7 7

5) 15 ÷ 19 > 11 ÷ 19 6) 3 ÷ 5 > 3 ÷ 9
18 20 18 20 4 10 4 14

7) 10 ÷ 9 < 10 ÷ 1 8) 10 ÷ 4 > 8 ÷ 4
13 13 9 8 10

9) 8 ÷ 4 > 6 ÷ 3 10) 12 ÷ 8 < 10 ÷ 3
12 4 12 3 24 10 20 10

2 เติมตวั เลขแสดงจ�ำ นวนใน

1) 6 ÷ 3 = 6÷ 6 2) 5 ÷ 1 > 5 ÷ 1
4 8 9 5 9

จำ�นวนนับต้งั แต ่ 1 - 4

3) 2 ÷ 3 < 2 ÷ 1 หรือ 2 4) 1 ÷ 1 = 6 ÷ 3
3 3 2 4 12 12

5) 4 ÷ 2 > 4 ÷ 3 6) 1 ÷ 7 < 1 ÷ 7
9 9 5 4 10 3 10

จำ�นวนนับต้ังแต่ 4 เป็นต้นไป

40 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

74 แบบฝึกหดั รายวชิ าพ้นื ฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษสว่ น

แบบฝึกหดั 1.19

แสดงวธิ คี ิดและวิธที าำ
1 กลอยทำ�ก�รบ้�นคณิตศ�สตร์ใชเ้ วล� 23 ชว่ั โมง และวิทย�ศ�สตร์ใช้เวล� 114 ช่วั โมง
กลอยทำ�ก�รบ้�นทัง้ สองวิช�ใช้เวล�กี่ช่ัวโมง

วิธคี ดิ

เวล�ทงั้ หมดท่ใี ชท้ �ำ ก�รบ้�น

วิช�คณติ ศ�สตร์ 2 ชั่วโมง วิช�วิทย�ศ�สตร์ 1 1 ช่ัวโมง
3 4

ว...ิธ..ีท..ำา.. . ......ก..ล...อ..ย..ท...�ำ .ก...�..ร..บ..�้..น...ว.ชิ...�..ค..ณ...ติ...ศ..�..ส..ต..ร..์ใ..ช..เ้.ว..ล...�............................................2..............ช..ว่ั..โ..ม..ง.......
3

................แ..ล...ะ..ว..ิช..�..ว..ทิ ..ย...�.ศ...�..ส..ต..ร..์ใ..ช..้เ.ว..ล..�.. .... ...... .................................................1...41..............ช..ั่ว..โ..ม..ง.......
................ด..งั..น...ั้น.. . .ก...ล..อ..ย...ท..ำ�..ก..�..ร..บ...้�.น...ท..งั้..ส..อ...ง..ว..ิช..�..ใ.ช..้เ..ว..ล..�..........32....+...1...14......=......32.....+....45..............ช..ัว่..โ..ม..ง.......
..........................................................................................................=......1.8..2...+....11..25...........ช..ว่ั..โ..ม..ง.......
..........................................................................................................=......12...32....................ช..ว่ั..โ..ม..ง.......
..........................................................................................................=......1...11..21..................ช..วั่..โ..ม..ง.......
ต...อ..บ.........1..11...21......ช...ว่ั ..โ.ม..ง.....................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................

| 41สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหัดรายวชิ าพืน้ ฐาน | คณติ ศาสตร์ ป.5 17
บทที่ 1 | เศษสว่ น

2 ลุงมีท่ดี นิ 2 7 ไร ่ ปลูกมะน�ว 1290 ไร ่ ทีด่ ินท่เี หลือปลกู มะม่วง ลงุ ปลูกมะม่วงก่ไี ร่
8

วิธคี ดิ

ทีด่ นิ 2 7 ไร่
8

ปลูกมะน�ว 19 ไร่ ปลูกมะม่วง
20

.ว..ิธ..ที ...ำา.. ......ล...งุ .ม...ีท..่ดี...ิน..........................................................................2..78..........ไ.ร..่.................................
. ...............ป...ล..กู ..ม...ะ..น..�..ว......................................................................1..9..........ไ.ร..่ .................................

20
. ...............ด...งั .น...ั้น.. .. .ล..ุง..ป..ล...ูก..ม..ะ..น...�..ว............2...87.....−... ..12...09.....=......2..8.3.....−.. ...12..09............ไ.ร..่.................................
.................................................................................=......1..4.1.0.5.....−.. ...34..80..........ไ.ร..่.................................
.................................................................................=......47...07........................ไ.ร..่.................................
.................................................................................=......1...34..07......................ไ.ร..่.................................
.ต..อ...บ........1...34..70.......ไ.ร..่.........................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................

42 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

75 แบบฝกึ หัดรายวชิ าพ้ืนฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษส่วน

3 แกว้ มสี ้ม 20 ผล แบง่ ให้เพอื่ น 25 ของสม้ ท่มี ีอยู ่ แกว้ แบง่ ส้มให้เพ่อื นกีผ่ ล
วธิ ีคิด

สม้ 20 ผล

แบง่ ใหเ้ พอ่ื น 2 ของสม้ ที่มีอยู่
5

.ว..ิธ..ีท...าำ .. ......แ...ก..้ว..ม..ีส...้ม.............................................................2..0.........ผ...ล.......................................
. ...............แ...บ..่ง..ใ.ห...เ้ .พ...ือ่ ..น..........................................................2.........ข...อ..ง..ส..ม้ ..ท...่ีม..อี..ย...ู่ .....................

5
. ...............ด...ัง.น...้ัน... . .แ..ก..้ว..แ...บ..่ง..ส..ม้ ..ใ..ห..เ้..พ..ือ่...น.............25.....×.....2..0.....=.....8.........ผ...ล.......................................
.ต..อ...บ.......8... . .ผ..ล..........................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................
..............................................................................................................................................

| 43สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หดั รายวชิ าพื้นฐาน | คณิตศาสตร์ ป.5 17
บทที่ 1 | เศษส่วน

4 ช�่ งก่อสร�้ งน�ำ เหลก็ ย�ว 553 เมตร ม�ตัดเป็นเสน้ ย�วเสน้ ละ 125 เมตร จะตดั ไดก้ ี่เส้น
วธิ คี ดิ

เหลก็ ย�ว 5 3 ม.
5

...

ย�วเสน้ ละ 1 2 ม.
5

.ว..ิธ..ที ...าำ .. ......ช...่�.ง..ก..อ่...ส..ร..้�..ง..น..ำ�..เ.ห...ล..ก็ ..ย..�..ว.. ............................................5...53..............เ.ม..ต...ร..............................
. ...............ม...�..ต..ัด..เ.ป...น็ ...เ.ส..น้ ... .ย..�..ว..เ.ส..้น...ล..ะ............................................1...25..............เ.ม..ต...ร..............................
. ...............ด...งั .น...ัน้ .. .. .จ..ะ..ต..ดั...ไ.ด..้....................5...35.....÷....1..25.......=......2.5.8.....÷.....57...............เ.ส..้น.................................
.................................................................................=......2.5.8.....×......75..............เ.ส..้น.................................
.................................................................................=......4...........................เ.ส..น้ .................................
.ต..อ...บ.........4... . .เ.ส...้น..............................................................................................................................
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44 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

76 แบบฝกึ หดั รายวิชาพนื้ ฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษส่วน

5 แมใ่ ชแ้ ชมพูสระผมไปแล้ว 51 ขวด ยังเหลืออกี 43 ขวด เดิมแมม่ ีแชมพูสระผมเท่�ใด

วธิ คี ิด

ใชไ้ ป 1 ขวด
5

เหลือ 3 ขวด
4

ว...ิธ..ีท..าำ.. .......แ..ม...่ใ.ช..แ้...ช..ม..พ...ูส..ร..ะ..ผ...ม..ไ..ป..แ...ล..้ว.. ........................................................15............ข..ว..ด.......................
................ย..ัง..เ.ห...ล..อื ..อ...กี .................................................................................34............ข..ว..ด.......................
................ด..งั..น...ั้น.. . ..เ.ด..ิม..แ...ม..ม่ ..แี...ช..ม..พ...ูส..ร..ะ..ผ...ม................15.....+.....43......=......2.4.0.....+.....21...05............ข..ว..ด.......................
...........................................................................................=......12..09.........................ข..ว..ด.......................
.ต..อ..บ........1...9.....ข..ว..ด..............................................................................................................................

20
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| 45สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหัดรายวิชาพนื้ ฐาน | คณติ ศาสตร์ ป.5 17
บทท่ี 1 | เศษส่วน

6 วันแรกตน้ ข่จี ักรย�นไดร้ ะยะท�ง 5 3 กิโลเมตร วันที่สองไดร้ ะยะท�ง 4170 กิโลเมตร
8

ต้นขีจ่ ักรย�น 2 วนั ได้ระยะท�งต่�งกนั กีก่ ิโลเมตร

วธิ คี ิด 5 3 กม.
8
วันเเรก
วนั ทส่ี อง 4170 กม. ระยะท�งทต่ี ่�งกนั

.ว..ิธ..ที...าำ .. .....ว..ัน..แ..ร..ก...ต..น้ ..ข...จ่ี ..ัก..ร..ย..�..น...ไ.ด...ร้ .ะ...ย..ะ..ท..�..ง.. .............................................................5...38..........ก..โิ .ล...เ.ม..ต...ร
. ..............ว..ัน..ท...สี่ ..อ..ง..ไ.ด...ร้ ..ะ..ย..ะ..ท...�..ง...............................................................................4..1.7.0..........ก..โิ .ล...เ.ม..ต...ร
. ..............ด..ัง..น..นั้... . .ต..น้...ข..จี่..ัก...ร..ย..�..น.. .2... .ว..นั .. ..ไ.ด..ร้..ะ..ย...ะ..ท..�..ง..ต..�่..ง..ก..นั.....5...38....−... .4..1.7.0.....=.....4.8.3....−....14..70.............ก..ิโ.ล...เ.ม..ต...ร
............................................................................................................=.....2..4.1.0.5....−... .1.4..8.0.8.......ก..ิโ.ล...เ.ม..ต...ร
............................................................................................................=.....42..70.......................ก..โิ .ล...เ.ม..ต...ร
.ต..อ...บ........42..70.....ก..ิโ..ล..เ.ม...ต..ร.....................................................................................................................
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46 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

77 แบบฝึกหดั รายวชิ าพนื้ ฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษสว่ น

7 ไก่ตัวเมยี ตัวหนงึ่ หนกั 125 กโิ ลกรัม ไก่ตัวเมยี หนกั นอ้ ยกว�่ ไก่ตัวผู้ 1270 กิโลกรมั
ไก่ตวั ผู้หนกั กี่กโิ ลกรัม

วธิ คี ิด

ไกต่ วั เมยี 1 2 กก. หนกั นอ้ ยกว่� 1207 กก.
ไก่ตวั ผู้ 5

ว...ิธ..ีท..ำา.. .....ไ..ก..ต่ ..ัว..เ.ม...ยี ..ต..วั..ห...น..ง่ึ..ห...น..กั... . ............................................................1...52.............ก..ิโ.ล...ก..ร..มั .................
..............ไ..ก..่ต..วั..เ.ม...ยี ..ห...น..ัก..น...อ้ ..ย..ก...ว..�่ ..ไ.ก..ต่...ัว..ผ..ู้ .................................................1...7.............ก..ิโ.ล...ก..ร..มั .................

20
..............ด..งั..น...ั้น.. . ..ไ.ก..ต่...ัว..ผ..หู้ ...น..กั.. ...........................1...52.....+.....12..70......=......57.....+.....12..07...............ก..โิ .ล...ก..ร..มั .................
...........................................................................................=......22..80.....+.....21..07.............ก..โิ .ล...ก..ร..ัม.................
...........................................................................................=......24..50.........................ก..ิโ.ล...ก..ร..ัม.................
...........................................................................................=......49...........................ก..ิโ.ล...ก..ร..ัม.................
...........................................................................................=.....2...41.........................ก..ิโ.ล...ก..ร..ัม.................
ต...อ..บ........2...41.....ก..ิโ..ล..ก..ร..มั ........................................................................................................................
.......................................................................................................................................................
.......................................................................................................................................................

| 47สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หดั รายวิชาพน้ื ฐาน | คณิตศาสตร์ ป.5 17
บทท่ี 1 | เศษสว่ น

8 พงศส์ งู 171 เซนตเิ มตร เพชรสูง 23 ของคว�มสูงของพงศ ์ เพชรสูงก่ีเซนตเิ มตร

วิธีคิด

171 ซม.

2 ของคว�มสูงของพงศ์
3

พงศ์ เพชร

ว..ิธ...ีท..าำ.. .......พ...ง.ศ...์ส..งู .. .................................................1..7...1.........เ..ซ..น...ต..ิเ.ม..ต...ร.............................................
................เ.พ...ช..ร..ส..ูง.......................................................23.........ข...อ..ง..ค..ว..�..ม..ส...งู .ข...อ..ง..พ..ง..ศ...์ ...........................
................ด..งั..น...น้ั .. . .เ..พ..ช...ร..ส..ูง.............32.....×.....1..7..1......=.....1..1..4..........เ..ซ..น...ต..ิเ.ม..ต...ร.............................................
ต...อ..บ........1..1...4.....เ.ซ..น...ต..ิเ.ม...ต..ร.................................................................................................................
......................................................................................................................................................
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48 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

78 แบบฝึกหัดรายวิชาพ้ืนฐาน | คณติ ศาสตร์ ป.5

บทที่ 1 | เศษสว่ น

9 ป้�มีน้ำ�เช่ือม 514 ลติ ร ใช้ทำ�ขนมคร้งั ละ 78 ลิตร ป้�ใช้นำ้�เช่อื มทำ�ขนมไดท้ งั้ หมดก่ีคร้ัง

วธิ ีคิด

...

น้ำ�เชื่อม 5 1 ล.
4

ทำ�ขนมคร้งั ละ 7 ล.
8

ว...ธิ ..ที ..าำ.. .....ป...�้ ..ม..ีน...้�ำ .เ..ช..ื่อ..ม... ....................................................................................5...41...........ล..ิต...ร.............
..............ใ..ช..ท้ ..ำ�..ข...น..ม...ค..ร..ัง้ ..ล..ะ...................................................................................78...........ล..ติ...ร.............
..............ด..งั..น...นั้ .. . ..ป..้�..ใ.ช...้น..ำ้�..เ.ช...อื่ ..ม..น...ที้ ...�ำ .ข...น..ม...ไ.ด..ท้...ง้ั ..ห..ม...ด............5...41.....÷....87.....=.....2..4.1.....÷.....78...........ค..ร..ั้ง..............
.......................................................................................................=.....2..4.1.....×.....78...........ค..ร..ั้ง..............
.......................................................................................................=.....6........................ค..ร..ง้ั..............
ต...อ..บ........6.. . ..ค..ร..ั้ง................................................................................................................................
......................................................................................................................................................
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| 49สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหัดรายวิชาพน้ื ฐาน | คณิตศาสตร์ ป.5 17
บทที่ 1 | เศษส่วน

10 ป้�ด�ตดั ผ�้ 634 เมตร เป็นชนิ้ ชิน้ ละเท่� ๆ กนั ได้ 9 ช้นิ ผ้�แต่ละชิ้นย�วกีเ่ มตร
วธิ คี ดิ

ผ้�ย�ว 6 3 ม.
4

คว�มย�วผ้�แต่ละชิ้น

ว..ธิ...ีท..าำ.. .......ป...้�.ด...�..ม..ีผ..้�.. ...........................................................................6..34...........เ.ม..ต...ร.........................
................ต..ดั...ผ..้�..เ.ป...น็ ..ช...น้ิ .. .ช...้นิ ..ล..ะ..เ..ท..�่.. .ๆ... .ก..นั ... .ไ.ด..้...........................................9..........ช..้ิน.............................
................ด..ัง..น...นั้ .. . .ผ...้�..แ..ต..่ล..ะ...ช..้ิน..ย...�..ว.......................6...34....÷.....9......=......2.4.7.....÷.....9..........เ.ม..ต...ร.........................
...........................................................................................=......2.4.7....×....19............เ.ม..ต...ร.........................
...........................................................................................=......34......................เ.ม..ต...ร.........................
ต...อ..บ...........3.....เ.ม..ต...ร...........................................................................................................................

4
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50 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

79 แบบฝกึ หัดรายวชิ าพน้ื ฐาน | คณิตศาสตร์ ป.5

บทที่ 1 | เศษส่วน

แบบฝกึ หัด 1.20

แสดงวธิ ที ำา

1 1134 + 14 − 5
7

.ว..ิธ..ที...าำ ............1..1.3..4....+......41.....−.. ...75.......=......11...74....+......14.....−.. ...57...........................................................
....................................................=......11..74....××....22....+.....41...××....77.....−.. . ..75...××....44.......................................
....................................................=......23...84....+.....2..7.8.....−.. . .22...08.......................................................
....................................................=......22...81...............................................................................
....................................................=.......43.................................................................................
.ต...อ..บ........43..............................................................................................................................
............................................................................................................................................

............................................................................................................................................

2 118 − 130 × 2 ตัวอย่�ง

.ว..ิธ..ีท...าำ .............1...18.....−.....1.3.0.....×.....2......=.......89.....−.. . ..1.3.0......×....2...........................................................
....................................................=.......89.....−.. . ..3..1.×.0...2................................................................
....................................................=.......89.....−.. . ..53.......................................................................
....................................................=......98....××...55.....−... . .35....××...88..........................................................
....................................................=......44...05....−... . .42...40...................................................................
....................................................=......42...01...............................................................................
.ต...อ..บ........2..1............................................................................................................................

40
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| 51สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหัดรายวิชาพ้ืนฐาน | คณติ ศาสตร์ ป.5 18
บทท่ี 1 | เศษส่วน

3 4 + 2 + 3
9 3 4

.ว..ธิ ..ที ...ำา................49.....+.....23......+.....34.......=......49....××...44.....+.....23....××...11...22.....+....34....××...99.................................................
....................................................=......31...66....+.....23...46....+.....32...67.................................................................
....................................................=......63...76.........................................................................................
....................................................=......1...33..61.......................................................................................
.ต...อ..บ.......1...33..61....................................................................................................................................
......................................................................................................................................................

......................................................................................................................................................

......................................................................................................................................................

4 10 × 125 × 5
21 14
ตวั อย�่ ง

.ว..ิธ..ที...ำา..........21...01.....×....1...52.....×.....1.5.4.......=......12...01....×......57.....×.....1.5.4...................................................................
....................................................=.......21...01...××....75...××....1.5.4........................................................................
....................................................=......2.5..1.........................................................................................
.ต...อ..บ.........5.......................................................................................................................................

21
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......................................................................................................................................................

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52 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

80 แบบฝกึ หดั รายวิชาพืน้ ฐาน | คณิตศาสตร์ ป.5

บทท่ี 1 | เศษส่วน

5 14 ÷ (152 × 185)
45
ตวั อย�่ ง

.ว..ธิ..ีท...าำ ..........41..54.....÷....(.1..5.2....×.....1.8.5...).....=......41..45.....÷.....(.1.5.2....××...1.8..5..).................................................................
....................................................=......14..54.....÷.....92................................................................................
....................................................=......14..45.....×.....29................................................................................
....................................................=......14..54....××....29..................................................................................
....................................................=.......57...........................................................................................
....................................................=......1...52.........................................................................................
.ต...อ..บ........1...52.....................................................................................................................................
......................................................................................................................................................

6 7 + 9 ÷ 175
6 14
ตวั อย�่ ง

.ว..ิธ..ีท...ำา............76......+....1..9.4....÷.....1...57.......=.......67.....+....1..9.4....÷.....1.7.2....................................................................
....................................................=.......76.....+.....1.9.4....×.....1.7..2...................................................................
....................................................=.......76.....+....1..9.4...××....1.7.2......................................................................
....................................................=.......76.....+.....38.................................................................................
....................................................=......67....××...44.....+.....38....××...33....................................................................
....................................................=......22..48.....+.....2.9.4..............................................................................
....................................................=......32..74..........................................................................................
.ต...อ..บ........1..12..43..................................=......1..21...43.......................................................................................

| 53สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หัดรายวชิ าพน้ื ฐาน | คณิตศาสตร์ ป.5 18
บทที่ 1 | เศษส่วน

7 ( 7 + 194) ÷ 1 5
6 7
ตัวอย�่ ง

.ว..ิธ..ที...ำา...........(..67.....+....1..9.4..)...÷....1...57.......=......(..67.....+....1..9.4..).....÷.....1.7.2................................................................
....................................................=......(.76....××...77.......+....1..9.4...××....33...)...÷.....1.7.2..................................................
....................................................=......(.44..29.....+.....24...27..).....÷.....1.7.2..............................................................
....................................................=......47..62.....÷.....1.7.2..............................................................................
....................................................=......47..26.....×.....1.7.2..............................................................................
....................................................=......47..26....××...1..7.2................................................................................
....................................................=......11..89..........................................................................................
.ต..อ...บ.......1...1.1.8..................................=......1..1..1.8.......................................................................................

8 3 3 × 6 ÷ 1180
4 25
ตวั อย�่ ง

.ว..ธิ..ีท...าำ ........3...34.....×.....2.6.5.....÷.....1..1.8.0.......=......1.4.5.....×.....2.6.5......÷.....11..80.................................................................
....................................................=.......1.4..5...××....26..5......÷.....11..80..................................................................
....................................................=......1.9.0.....÷.....11..80..............................................................................
....................................................=......1.9.0.....×.....11..08..............................................................................
....................................................=......1.9.0....××...11...08................................................................................
....................................................=.......12...........................................................................................
.ต..อ...บ........1........................................................................................................................................

2
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54 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

81 แบบฝึกหัดรายวิชาพนื้ ฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษส่วน

9 1288 ÷ 214 ÷ 12
14
ตวั อย่�ง

.ว..ธิ..ที...ำา............1..2.8.8....÷......2..41......÷....11...24......=......23..68.....÷.....49......÷.....11..24................................................................
.......................................................=......32..68.....×.....94......×....11...24................................................................
.......................................................=......23...86...××....49...××....11..24......................................................................
.......................................................=.......23........................................................................................
.ต...อ..บ........2........................................................................................................................................

3
......................................................................................................................................................

......................................................................................................................................................

......................................................................................................................................................

10 30 ÷ 183 × 9
40
ตวั อย่�ง

.ว..ธิ ..ีท...าำ ..............3..0.....÷....1...83......×....4.9..0......=......3...0....÷.....1.8.1.....×....4..9.0...............................................................
.......................................................=......3...0....×.....1.8.1.....×.....4.9.0...............................................................
.......................................................=......3...0.1..1×....×8...4.×..0..9.......................................................................
.......................................................=......15..41.......................................................................................
.......................................................=......4...11..10....................................................................................
.ต...อ..บ........4..11..01....................................................................................................................................
......................................................................................................................................................

......................................................................................................................................................

| 55สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหดั รายวชิ าพืน้ ฐาน | คณติ ศาสตร์ ป.5 18
บทที่ 1 | เศษส่วน

แบบฝึกหดั 1.21

แสดงวธิ คี ดิ และวิธีทาำ

1 ครูมเี ชอื กย�ว 12 3 เมตร ตัดเชือกให้นกั เรยี นใชท้ ำ�กิจกรรมผูกเงอ่ื น 5 คน
5

คนละ 145 เมตร ครูจะเหลอื เชือกย�วก่เี มตร

วิธีคิด

เชอื กย�ว 12 3 ม.
5

ตัดให้นักเรยี น ที่เหลอิื

.ว..ิธ..ที ..ำา.. .. . . .ค..ร..ูม...ีเ.ช..ือ..ก...ย..�..ว.. . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . . .. . . 1. . .2 .. 53. . . . . ........เ.ม...ต..ร............................
. . . . . . . .. . . . . .น...ำ�..ไ.ป...ต..ดั ..ใ..ห..น้...ัก..เ.ร..ีย...น..............................................................5............ค..น................................
. . . . . . . .. . . . . .ค...น..ล..ะ... ............ . .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . . ......... . ..... .1...45.. . . . . .. . . . . .เ .ม. . .ต..ร. . . . .. . . . . . . .. . . . . . . .. . . . . . .
. . . . . . . .. . . . . .เ.ช...ือ..ก..ท...ี่ต..ดั ...ใ.ห...้น..กั ..เ..ร.ีย...น..ย...�.ว.. ........... . .. . . . . 5. .. . . ×. . . . .1. . 54. . . . . .=. . . . .5 . . .. ×. . . . .95..............เ.ม...ต..ร............................
........................................................................................=.....9.......................เ.ม...ต..ร............................
. . . . . . . .. . . . . .ด...ัง.น...้ัน.. .. .ค..ร..เู .ห...ล..อื ..เ.ช...ือ..ก..ย...�.ว.. ........... .....1. .2...35.....−.....9.....=..... 6.5.3.... .−....9. ..... ......เ.ม...ต..ร. .. . ........................
........................................................................................=.....6.5.3.....−....4..5.5.........เ.ม...ต..ร............................
........................................................................................=.....1.5.8.....................เ.ม...ต..ร............................
........................................................................................=.....3..53.....................เ.ม...ต..ร............................
.ต..อ..บ....... . . . . . .3 .. . 53. . . . . ..เ.ม..ต...ร....................................................................................................................
......................................................................................................................................................

56 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

82 แบบฝกึ หดั รายวิชาพื้นฐาน | คณิตศาสตร์ ป.5

บทท่ี 1 | เศษสว่ น

2 แมค่ ้�มนี ำ�้ ต�ลปี๊บ 8543 กิโลกรมั ข�ยไปแลว้ 2414 กิโลกรมั น้�ำ ต�ลปบ๊ี ที่เหลอื นำ�ม�ใส่ถงุ
ถุงละ 112 กิโลกรมั จะได้น้ำ�ต�ลปบี๊ กี่ถุง

วธิ คี ดิ

ข�ยไปแลว้ 24 1 กก.
4

น�้ำ ต�ลปีบ๊ 85 3 กก. ...
4

ถุงละ 1 1 กก.
2

.ว..ธิ ..ีท...ำา.. . . . .แ..ม...่ค..�้..ม..ีน...�ำ้ ..ต..�..ล..ป...ี๊บ.. .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . . .. . . .8..5...34..............ก..โิ..ล..ก..ร..มั ......
. . . . . . .. . . . . . .ข...�..ย..ไ.ป...แ..ล..้ว.. ..... .. . . . . . . .. . . . . . . .. . . . . . . .. . . . . ... . . . .. ................... ...... ...... . . . .. . . . . . .2. .4...14..............ก..โิ..ล..ก..ร..มั ......
. . . . . . .. . . . . . .เ..ห..ล..ือ...น..�ำ้..ต..�..ล...ป..ี๊บ........................................8..5...34.....−.....2..4...41......=.....3..44..3.....−....9.4.7.............ก..โิ..ล..ก..ร..มั ......
......................................................................................................=.....2..44..6........................ก..โิ..ล..ก..ร..มั ......
......................................................................................................=.....1..22..3........................ก..โิ..ล..ก..ร..มั ......
. . . . . . .. . . . . . .น...้�ำ ..ต..�..ล..ป...ี๊บ..ท...เี่ .ห...ล..ือ.. .น...�ำ ..ม..�..ใ.ส...ถ่ ..งุ .. .ถ..ุง..ล..ะ....................................................1...12..............ก..โิ..ล..ก..ร..มั ......
. . . . . . .. . . . . . .ด...ัง.น...้นั ... . .จ..ะ..ไ..ด..้น..ำ้�..ต...�..ล..ป..บ๊ี................................1...22..3.....÷....1...21......=.....1..22..3.....÷.....32..............ถ..งุ..............
......................................................................................................=.....1..22..3.....×.....23..............ถ..งุ..............
......................................................................................................=.....4..1..........................ถ..ุง..............
ต...อ..บ........4...1.. . .ถ...ุง................................................................................................................................
.......................................................................................................................................................

| 57สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หัดรายวิชาพืน้ ฐาน | คณิตศาสตร์ ป.5 18
บทท่ี 1 | เศษสว่ น

3 รตที ำ�ง�นไดร้ ับเงินเดือน เดอื นละ 28,000 บ�ท จ่�ยค�่ ผ่อนบ้�นเดอื นละ 73 ของเงินเดอื นที่ได้รบั
ทเ่ี หลือเปน็ ค่�ใชจ้ �่ ยส่วนตวั รตีจะเหลอื เงินค�่ ใชจ้ �่ ยสว่ นตวั เดือนละก่ีบ�ท

วธิ ีคิด

เงินเดอื น 28,000 บ�ท

ค่�ผ่อนบ�้ น 3 ของเงินเดือน ค�่ ใช้จ�่ ยสว่ นตัว
7

.ว..ธิ ..ที ...าำ .. ...ร..ต...ีท..ำ�..ง..�..น..ไ..ด..้เ.ง..ิน..เ..ด..ือ..น... .เ.ด...อื ..น..ล...ะ.. .........................................2..8...,.0..0..0........บ..�..ท...........................
. ............จ...�่ .ย...ค..�่ ..ผ..่อ...น..บ...�้ ..น..เ.ด...ือ..น..ล...ะ..............................................................3........ข..อ..ง..เ.ง..นิ ...เ.ด..อื..น...ท..ไ่ี..ด..้ร..ับ...

7
. ............ร..ต...ีจ..�่ ..ย..ค..่�..ผ...อ่ ..น..บ...้�..น..เ..ด..ือ..น...ล..ะ.. ......... .............................37.....×.....2..8...,.0..0..0......=....1...2..,.0...0..0........บ..�..ท....
. ............ด...ัง.น...ัน้ ... . .ร..ต..ีเ.ห...ล..ือ..เ..ง.ิน...ค..�่..ใ.ช...้จ..่�..ย..ส..่ว..น...ต..วั..เ.ด...ือ..น...ล..ะ......2...8..,.0..0...0...−....1..2...,.0..0..0......=.....1..6..,.0...0..0........บ..�..ท....
.ต..อ...บ.......1...6..,.0..0...0.....บ..�..ท.....................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................

58 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

83 แบบฝกึ หัดรายวชิ าพื้นฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษส่วน

4 นอ้ ยซ้ือปล�กะพง 152 กโิ ลกรัม ซอ้ื หมกึ ม�กกว่�ปล�กะพง 21 กโิ ลกรัม
และซอ้ื หอยแครงน้อยกว�่ หมกึ 14 กโิ ลกรัม นอ้ ยซอื้ หอยแครงกีก่ ิโลกรมั

วธิ ีคดิ

ปล�กะพง 152 กก. ม�กกว่�ปล�กะพง 1 กก.
หมกึ 2

หอยแครง น้อยกว�่ หมกึ 1 กก.
4

ว..ธิ...ีท..ำา.. ......น..้อ...ย..ซ..้ือ...ป..ล..�..ก...ะ..พ..ง.. ...... ............... ...... ....... ............. ..............1...25...............ก...โิ .ล..ก..ร..มั...................
...............น..้อ...ย..ซ..ื้อ...ห..ม..ึก...ม..�..ก..ก...ว..่�.ป...ล..�..ก..ะ...พ..ง.. . . . .. . . . . . . .. . . . . . . .. . ..... .................1...... . . .. . . . . .ก .. .โิ . ล..ก..ร..มั ..... ..............

2
...............น..้อ...ย..ซ..ื้อ...ห..ม..กึ... . . ..............................1...52.....+.....12......=......57......+......21..................ก...โิ .ล..ก..ร..มั...................
.....................................................................................=.....11..40.....+....1..5.0.................ก...โิ .ล..ก..ร..มั...................
.....................................................................................=.....11..90.............................ก...โิ .ล..ก..ร..มั...................
...............แ..ล..ะ..ซ...อื้ ..ห...อ..ย..แ..ค...ร..ง.น...้อ..ย..ก...ว..�่ ..ห..ม..ึก... . . . .... ....... ............. . . .. . . . . . .. . . . . .41 . .. .............ก...โิ .ล..ก..ร..มั...................
...............ด..งั..น..ัน้... . .น...้อ..ย..ซ...ื้อ..ห...อ..ย..แ..ค...ร..ง. .......... ....11.. 90.....−.. .. . 14. . . ...=......23..08......−......2.5.0..............ก...โิ .ล..ก..ร..มั...................
.....................................................................................=......23..03............................ก...โิ .ล..ก..ร..มั...................
.....................................................................................=.....1..21..03...........................ก...โิ .ล..ก..ร..มั...................
ต...อ..บ.......1...21...03.....ก...โิ .ล..ก..ร..ัม.....................................................................................................................
......................................................................................................................................................

| 59สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝกึ หดั รายวิชาพนื้ ฐาน | คณติ ศาสตร์ ป.5 18
บทที่ 1 | เศษสว่ น

5 แพรใชร้ ิบบ้นิ ผูกของขวัญ 8 กล่อง กล่องละ 35 เมตร เหลอื รบิ บ้ิน 4 1 เมตร
2

เดมิ แพรมรี บิ บนิ้ ย�วเท่�ใด

วิธคี ดิ

คว�มย�วรบิ บน้ิ ท้งั หมด

35 ม. เหลือ 412 ม.

.ว..ิธ..ีท...าำ .. .....แ..พ...ร..ใ..ช..ร้ ..ิบ..บ...้นิ ..ผ...กู ..ข..อ...ง.ข...ว..ญั ... ......... ...... ...............................................8...........ก...ล..่อ..ง................
. ..............ก...ล..อ่ ..ง..ล..ะ.. ........ ....... ...... .............. ...... ...............................................3...........เ..ม..ต..ร.................

5
. ..............ค...ว..�.ม...ย..�..ว..ร..บิ ..บ...้ิน...ท..่ีใ.ช...้ผ..กู..ข...อ..ง..ข..ว..ญั... ..... . . . .. . . . ................8.....×.....53.....=......2.5.4...........เ..ม..ต..ร.................
. ..............แ..ล...ะ..เ.ห...ล..อื ..ร..ิบ...บ..้ิน... ... ...... .............. ...... ........ ............... ....................4....21...........เ..ม..ต..ร.................
. ..............ด...ัง.น...ั้น.. .. .เ.ด..มิ...แ..พ...ร..ม..รี ..บิ ..บ...้ิน..ย...�..ว.. . . . . . . .. . . . .......2.5.4.....+.....4...21.....=.....2.5..4....+.....29..............เ..ม..ต..ร.................
................................................................................................=.....41...08....+.....14...50...........เ..ม..ต..ร.................
................................................................................................=......19..30.......................เ..ม..ต..ร.................
................................................................................................=.....9...1.3.0.....................เ..ม..ต..ร.................
.ต..อ...บ...... . . . . 9. .. 1. 3. 0. . . . ..เ.ม..ต...ร.....................................................................................................................
......................................................................................................................................................
......................................................................................................................................................

60 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

84 แบบฝึกหัดรายวชิ าพนื้ ฐาน | คณติ ศาสตร์ ป.5

บทท่ี 1 | เศษส่วน

6 ทพิ ย์ซ้อื เห็ดหหู นูแห้ง 43 กิโลกรัม ร�ค�กิโลกรัมละ 420 บ�ท ทพิ ย์จ�่ ยเงินใหแ้ มค่ �้
เปน็ ธนบตั รห้�รอ้ ยบ�ท 1 ฉบบั ทพิ ย์จะได้รบั เงินทอนเท�่ ใด

วธิ ีคดิ

เห็ดหหู นแู หง้ กก. ละ 420 บ�ท

ซ้อื 43 กก.

ว...ธิ ..ที ..าำ.. ......ท...ิพ..ย...์ซ..อ้ื ..เ.ห...็ด..ห...ูห..น...ูแ..ห...้ง. .. .............. ...... ........ ............ ......................3............ก...โิ .ล..ก..ร..มั.................
4

...............ร..�..ค..�..ก..โิ..ล..ก..ร..ัม...ล..ะ.. ... ...... .............. ...... ........ ............ .................4...2..0............บ...�..ท......................
...............ท...ิพ..ย...ซ์ ..้อื ..เ.ห...ด็ ..ห...หู ..น...แู ..ห...้ง.เ..ป..็น...เ.ง..นิ .. .... ...... ............43.....×.....4..2..0......=.....3...1..5............บ...�..ท......................
...............ท...ิพ..ย...จ์ ..่�..ย..เ.ง..ิน..ใ..ห..้แ...ม..่ค..�้.. .. .............. ...... ........ ............ .................5...0..0............บ...�..ท......................
...............ด..งั..น...น้ั .. . ..ท..พิ...ย..์จ..ะ..ไ..ด..้ร..บั ...เ.ง..นิ ..ท...อ..น.. .. . . . . . ..........5...0..0.....−.. . ..3..1..5... ...=.....1...8..5............บ...�..ท......................
.ต..อ...บ........1..8..5.....บ...�.ท...........................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................

| 61สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหดั รายวิชาพื้นฐาน | คณติ ศาสตร์ ป.5 18
บทท่ี 1 | เศษสว่ น

7 วรรณ�ซื้อส้มโอ 2 ลูก ลูกแรกหนัก 114 กิโลกรมั ลูกท่ีสองหนกั กว่�ลกู แรก 3 กิโลกรมั
10

วรรณ�ซ้อื สม้ โอทงั้ หมดก่ีกิโลกรัม

วิธคี ิด

ลกู แรก 1 41 กก. หนกั กว�่ ลกู แรก 130 กก. นำ้�หนกั ส้มโอ
ลูกทสี่ อง ทัง้ หมด

.ว..ิธ..ีท..ำา.. ......ส..้ม...โ.อ..ล...กู ..แ..ร..ก..ห...น..กั... . ...... .............. ...... ........ ............ ........................1...41.............ก..โิ .ล..ก...ร.มั............
...............ล..ูก...ท..่สี..อ...ง.ห...น...ัก..ก..ว..่�..ล..ูก..แ...ร..ก.. .......... ...... ........ ............ ..........................3..............ก..โิ .ล..ก...ร.มั............

10
. ..............ส..ม้...โ.อ..ล...ูก..ท...่ีส..อ..ง..ห..น...กั .. ..... . . . . . . .. . . . . . . .. . . . ..........1..41.....+.....1.3.0.....=.......45....+....1.3.0...............ก..โิ .ล..ก...ร.มั............
.................................................................................................=.....22...05....+.....2.6..0............ก..โิ .ล..ก...ร.มั............
.................................................................................................=.....23...10........................ก..โิ .ล..ก...ร.มั............
...............ด..ัง..น...้นั .. . ..ว..ร.ร..ณ....�.ซ...อื้ ..ส..ม้...โ.อ..ท...ั้ง..ห..ม...ด.. . . . .. . .........1...41.....+.....32..01.....=......54.....+.....23..01..............ก..โิ .ล..ก...ร.มั............
.................................................................................................=.....22...50....+.....32..01.............ก..โิ .ล..ก...ร.มั............
.................................................................................................=......52..06........................ก..โิ .ล..ก...ร.มั............
.................................................................................................=......1.5.4........................ก..โิ .ล..ก...ร.มั............
.................................................................................................=.....2...45........................ก..โิ .ล..ก...ร.มั............
ต...อ..บ....... . 2. . .45 . . .. .ก..โิ .ล...ก..ร..มั .......................................................................................................................

62 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

85 แบบฝกึ หดั รายวิชาพ้นื ฐาน | คณิตศาสตร์ ป.5

บทท่ี 1 | เศษสว่ น

8 แม่มีซอสปรงุ รส 54 ลติ ร วนั แรกใชไ้ ป 18 ลติ ร วันที่สองใชไ้ ปอกี 130 ลติ ร
แม่เหลอื ซอสปรงุ รสกลี่ ิตร

วิธคี ดิ

ซอสปรุงรส 4 ล.
5

วันแรก วันที่สอง เหลอื

1 ล. 3 ล.
8 10

.ว..ิธ..ีท..าำ.. ......แ..ม...ม่ ..ีซ...อ..ส..ป...ร..ุง.ร..ส.. .... ...... .............. ...... ........ ....... .......................4.................ล...ติ ..ร.....................
5

...............ว..ัน...แ..ร..ก..ใ.ช...ไ้ .ป... .. ....... ...... .............. ...... ........ ....... .......................1.................ล..ิต...ร.....................
8

. ..............ว..ัน...ท..ี่ส..อ...ง.ใ..ช..้ไ..ป..อ...กี .. .. ...... . . . ........... ...... ........ ....... .......................3.................ล...ติ ..ร.....................
10

...............ร..ว..ม..ส...อ..ง..ว..ัน.. .แ...ม..ใ่ .ช...้ซ..อ..ส...ป..ร..งุ..ร..ส.. .... . .. ....81.....+.....1.3.0......=......4.5.0.....+.....41..02................ล..ิต...ร.....................
........................................................................................=......14..07............................ล...ิต..ร.....................
...............ด..งั..น...ั้น.. . ..แ..ม..เ่ .ห...ล..ือ..ซ...อ..ส..ป...ร..ุง..ร.ส... . . . . . .. . .....54.....−.....14..70......=......34..02.....−.. .. .14..70................ล..ติ...ร.....................
........................................................................................=......41..50............................ล...ิต..ร.....................
........................................................................................=.......38.............................ล..ิต...ร.....................
ต...อ..บ.........38... . .ล...ติ ..ร..............................................................................................................................
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| 63สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหดั รายวชิ าพนื้ ฐาน | คณิตศาสตร์ ป.5 18
บทที่ 1 | เศษสว่ น

9 ทด่ี นิ ของพอ่ กบั ลุงอยตู่ ดิ กนั ทด่ี นิ ของลงุ มพี นื้ ท ่ี 2130 ไร ่ ที่ดนิ ของพอ่ มพี นื้ ท ี่ 341 ไร่
ลุงกบั พ่อต้องก�รถมท่ดี นิ ทง้ั หมด ซง่ึ ผู้รบั จ�้ งถมท่ีดนิ คิดร�ค�ไร่ละ 150,000 บ�ท

ผ้รู ับจ�้ งจะได้รบั เงนิ ค่�ถมทด่ี นิ เท่�ใด

วิธคี ิด

ทดี่ ินทงั้ หมด

ลุง 2 130 ไร่ พอ่ 3 1 ไร่
4

ว...ธิ ..ที ..าำ.. ......ท...่ีด..นิ ...ข..อ..ง..ล..งุ..ม..ีพ...้นื ...ท..่ี ...... .............. ...... ........ ....... ................. ............2..1..3.0................ไ..ร.่.............
...............ท...่ีด..นิ ...ข..อ..ง..พ...่อ..ม..พี...นื้ ...ท..่ ี. .... .............. ...... ........ ....... ................. ............3...41..................ไ..ร.่.............
...............ร..ว..ม..ท...ดี่ ..ิน...ท..งั้..ห...ม..ด.. ... ...... . . . . . . .. . . . . .............2..1..3.0....+.....3...41.....=......21..03.....+....1.4..3..................ไ..ร.่.............
................................................................................................=......24..06.....+....62...50..................ไ..ร.่.............
................................................................................................=.......1.2.1.0.1...........................ไ..ร.่.............
...............ผ..รู้..บั...จ..�้..ง..ค..ิด..ค...�่ ..ถ..ม..ท...ด่ี ..นิ...ไ.ร..่ล..ะ.. .. ..... ...... ........ ....... . . . .. . . . . . . .. . ... ..1..5..0...,.0..0...0.. ....... .........บ...�..ท...........
...............ด..ัง..น...ัน้ .. . ..ผ..ู้ร..ับ..จ...�้ .ง..จ..ะ..ไ..ด..ร้..บั...เ.ง..ิน..ค...่�.ถ...ม..ท...่ีด..นิ .. .. . . 1. .2 .1 .0. 1. . . .× . . .. .1 . . 5. . 0. .. ,. 0. . 0. . .0 .. . . .= . . . ..8..3..2...,.5..0...0.......บ...�..ท...........
ต...อ..บ....... .8..3..2...,.5..0...0.. . .บ...�..ท...................................................................................................................
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64 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

86 แบบฝึกหัดรายวชิ าพ้นื ฐาน | คณิตศาสตร์ ป.5

บทท่ี 1 | เศษส่วน

10 โรงเรียนแห่งหน่งึ มีนกั เรียนช�ย 76 ของจ�ำ นวนนกั เรียนหญิง ถ�้ มีนักเรยี นหญิง 105 คน
โรงเรียนนีม้ ีนักเรียนท้งั หมดกี่คน

วธิ ีคดิ

นักเรียนหญงิ 105 คน จำ�นวนนักเรียนทัง้ หมด
นกั เรยี นช�ย 6 ของจำ�นวนนกั เรียนหญิง
7

ว...ิธ..ีท..ำา.. ......โ.ร..ง..เ.ร..ีย..น...แ..ห...่ง..ห..น...ึง่ .ม...ีน..ัก...เ.ร..ีย..น..ช...�..ย.. ...... ........ ...........................6... ......ข..อ..ง..จ..�ำ..น...ว..น..น...กั ..เ.ร..ยี..น...ห..ญ....ิง.
7

...............ถ..้�..ม...นี ..ัก..เ..ร..ยี ..น..ห...ญ...ิง.. . ...... .............. ...... ........ .......................1..0...5.. ......ค..น...................................
...............จ..ะ..ม...นี ..ัก...เ.ร..ีย..น..ช...�..ย.. .. ...... .............. . .. . . . . . .. . . . . .76 . .. .× . . . 1. . .0. . 5......=......9...0.. ......ค..น... ...... ............ ..............
...............ด..งั..น...ั้น.. . ..โ.ร..ง..เ.ร..ีย..น..น...ี้ม..นี...กั ..เ.ร..ยี...น..ท...้งั .ห...ม..ด... . . . . . ..1..0..5... .+.. .9...0.. . . ..=.. . .1..9...5.. ......ค..น...................................
ต...อ..บ....... .1..9..5... . .ค..น..............................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................
......................................................................................................................................................

| 65สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

18

แบบฝึกหัด ทศนิยม

บทท่ี 2

แบบฝึกหัด 2.1

1 เขียนในรูปทศนิยม

1) 4 =....................0...4............................ 2) 9 =.....................0...0...9........................
10 100

3) 567 =....................0....5..6...7....................... 4) 31 =.....................3...1...........................
1000 10

5) 205 =....................2..0...5.......................... 6) 6923 =.....................6...9...2..3......................
10 1000

7) 38 =....................0...0..3...8....................... 8) 217 =.....................2...1...7........................
1000 100

9) 60 =....................6...0............................ 10) 1790 =.....................1...7...9..0....ห..ร..ือ...1....7..9.....
10 1000

2 เขียนในรูปเศษส่วน

1) 0.6 =....................6.............................. 2) 1.2 =.....................1..2..........................
10 10

3) 0.46 =....................4...6........................... 4) 3.8 =.....................3..8..........................
100 10

5) 0.367 =.....................3..6..7......................... 6) 2.96 =.....................2..9...6.......................
1000 100

7) 4.108 =...................4...1..0..8........................ 8) 10.001 =.....................1..0...0..0...1..................
1000 1000

9) 0.05 =......................5............................ 10) 20.70 =.....................2..0...7..0.....หริือ..2..0...7...
100 100 10

66 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

87 แบบฝกึ หัดรายวิชาพนื้ ฐาน | คณิตศาสตร์ ป.5
บทที่ 2 | ทศนยิ ม
3 แสดงวิธหี าผลลพั ธ์

1) 8.35 + 2.05 2) 4.5 + 0.63
..ว..ิธ..ที ...�ำ .......................8...3..5.................................. ...ว..ธิ ..ที...�ำ .....................4....5..0.................................
................................2...0..5....+.............................. ...............................0....6..3....+.............................
.............................1..0....4..0.................................. ...............................5....1..3.................................
.......................................................................
..ต..อ...บ......๑..๐.....๔...๐.....ห..ร..ือ.....๑...๐....๔............................ ......................................................................

...ต..อ...บ......๕....๑...๓.................................................

3) 0.19 + 0.008 3) 5.369 − 0.124
..ว..ิธ..ีท...�ำ .....................0....1..9..0................................. ..ว..ธิ ..ีท...ำ�.....................5....3..6..9.................................
..............................0....0..0..8...+.............................. ..............................0....1..2..4.....-............................
..............................0....1..9..8................................. ..............................5....2..4..5.................................
.......................................................................
..ต..อ...บ......๐....๑...๙..๘................................................. .......................................................................
..ต..อ...บ......๕.....๒...๔...๕................................................

5) 4.128 − 0.07 6) 10 − 2.9
..ว..ธิ ..ีท...ำ�.....................4....1..2..8................................. ..ว..ธิ ..ีท...�ำ.....................1...0...0...................................
..............................0....0..7..0....-............................. ................................2....9......-.............................
..............................4....0..5..8................................. ................................7....1...................................

....................................................................... .......................................................................

..ต..อ...บ......๔.....๐...๕..๘................................................. ..ต..อ...บ......๗.....๑......................................................

7) 7.64 + 0.019 + 0.5 8) 2 - (0.84 - 0.271)
..ว..ิธ..ีท...ำ�......0....8..4..0......................2....0..0...0..................
..ว..ิธ..ีท...ำ�.....................7....6..4..0................................. ................0...2..7...1...-.................0....5..6...9...-...............
..............................0....0..1..9....+............................. ...............0....5..6...9.....................1...4...3..1..................
..............................0....5..0..0................................. .......................................................................
..............................8....1..5..9................................. ..ต..อ..บ........๑....๔..๓...๑................................................
..ต..อ...บ......๘.....๑...๕...๙................................................

| 67สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี

แบบฝึกหดั รายวชิ าพน้ื ฐาน | คณติ ศาสตร์ ป.5 18
บทท่ี 2 | ทศนิยม

4 แสดงวิธีหาผลลัพธ์

1) 3 × 1 2) 7 × 4
5 2 10

ว....ิธ....ที......ำา......................53........×......21..........=........53........××......12.......................................................... ..ว....ธิ ....ีท....ำา..................1..7..0........×......4..........=..........7....1..×..0....4..........................................................
..............................=....1.3..0................................. ..............................=....21...08....=.....1.5.4.....=....2...45..........
...................................................................... ......................................................................
ต...อ..บ........3........................................................ .ต..อ..บ........2..54......................................................

10

3) 8 ÷ 1 4) 101060÷ 5
100 8

..ว..ธิ....ที......ำา..................1....08....0......÷........18..........==........1....880....0..×......×8........18............................................ วต..........ิธ.....อ.....ที.....บ..........าำ .........................2..........1..........10..........06..........0....................÷....................5....................====...............1.....151.....10.....101001.....06.....060660.....0.....000.....×..........×=÷.....×1..........5..........15156..........22..........5...............................................................................
....................................1..0..0...×...1........................
................................=.....6..4.....=.....1..6................... 625
.ต..อ..บ.......1..6......................1..0..0.........2..5..................

25

5 แสดงวิธีทาำ

1) ) ผง้ึ ซื้อแปรงสีฟนั 10.25 บาท และซอ้ื ยาสฟี นั 21.50 บาท ผงึ้ ตอ้ งจา่ ยเงนิ ท้ังหมดกบี่ าท
....ว..ธิ...ีท..ำา.....ผ..งึ้ ..ซ..อ้ื..แ...ป..ร..ง..ส..ีฟ...ัน............................................................1..0....2...5....บ...า..ท............................
...............ซ...้ือ..ย..า..ส..ฟี...นั .....................................................................2..1...5...0.....บ..า..ท............................
...............ด..งั..น...ัน้ ...ผ...งึ้ .ต...อ้ ..ง..จ..่า..ย..เ.ง..ิน...ท..ัง้..ห..ม...ด........1..0....2..5....+...2..1....5..0.....=.....3..1...7...5....บ...า..ท...........................
....ต...อ..บ.....๓...๑....๗..๕.....บ...า..ท.............................................................................................................

2) ป่นิ ซอื้ ก้งุ 1 กิโลกรมั นำาไปทำาอาหาร 0.75 กิโลกรมั ปนิ่ เหลอื ก้งุ ก่กี โิ ลกรมั
....ว..ิธ...ีท..ำา.....ป..ิ่น...ซ..อ้ื..ก...งุ้ ..............................................................................1....ก...ิโ.ล..ก...ร..มั ......................
...............น...าำ ..ไ.ป...ท..าำ..อ..า..ห...า..ร...............................................................0...7...5....ก...โิ .ล..ก...ร.ัม.......................
...............ด..ัง..น...้นั ...ป...น่ิ ...เ.ห..ล...ือ..ก..ุ้ง......................................1...-...0...7...5....=.....0...2...5....ก...ิโ.ล..ก...ร..ัม.....................
....ต...อ..บ.....๐....๒..๕.....ก...โิ .ล..ก...ร.ัม...........................................................................................................

68 | สถาบันส่งเสริมการสอนวิทยาศาสตร์และเทคโนโลยี