Oasis Math 3

Naming of a Quadrilateral A D
B C
While giving the name of the
quadrilateral, write all the four vertices
serially starting from any vertex like
quadrilateral ABCD or BCDA or CDAB
or DABC.

Name the following quadrilaterals and write their vertices, sides and angles:

A The name of quadrilateral
D
B

Sides : , , and

Angles: , , and

C Vertices: , , and

P Q The name of the quadrilateral
S
Sides , , and
M
N Angles: , , and

O R

Vertices: , , and

The name of the quadrilateral

P Sides: , , and

Angles: , , and

Vertices: , , and

Oasis School Mathematics Book-3 101

Drawing of a Quadrilateral

Look and learn.

Take any four points A, B, C and D as shown in the figure:
Use a ruler to join A and B. Similarly, join BC, CD and DA in order.

AA

D BD B

CC

Then, ABCD is a quadrilateral.

With the help of a ruler, join the given points in order to form
quadrilaterals and write their names.

PA B
Q

SR DC

W X MN
Z Y PO

102 Oasis School Mathematics Book-3

Circle

Take a coin. Place it on a sheet of paper. Draw along its edge. You get a
circle.

A circle is a round plane figure.
A circle has no vertices.

radius P circumference
O
O is the centre. centre
OP is the radius.

To the teacher
Draw a circle with the help of compass and give the concept of centre and
radius.

Name the centre and the radius of the given circles:

A Q MN R
O P

Centre Centre Centre S
Radius Radius Radius
Centre
Radius

Oasis School Mathematics Book-3 103

Identification of Rectangle and Square Q

Let's compare these two figures.

AB
P

S R
DC

Each angle in both figure is right angle.

Each side of first figure are equal. Only opposite sides of second figure
are equal. First figure is square and second figure is rectangle.

I remember! all sides I remember! opposite
of square are equal sides of rectangle are
and each angle is right equal and each angle

angle is right angle.

Colour the rectangle by blue and square by red.

Tick (√) the object having rectangular surface and cross (×) the object
having square.

104 Oasis School Mathematics Book-3

Eexercise

1. Draw three triangles of different sizes in your copy and name
them.

2. Draw three quadrilaterals of different sizes in your copy and name them.
3. Draw the following figures in your copy.

(a) ∆ABC (b) ∆PQR

(c) Quadrilateral ABCD (d) Quadrilateral PQRS

4. Measure the length of the radius of the given circles:

Radius = cm Radius = cm

5. Measure the length of each side of the given figures with the help of a
ruler:

P

A
S

Q

B C PQ = cm

AB = cm R QR = cm
BC = cm
AC = cm RS = cm

SP = cm

Oasis School Mathematics Book-3 105

6. Answer the following questions in one word.
a. How many sides does a triangle have?
b. How many angles does a triangle have?
c. Which instrument is used to measure the length of a
line segment?
d. How many angles does a quadrilateral have?
e. How many vertices does a quadrilateral have?

7. Write (T) for true statements and (F) for false ones:
a. A ruler is used to measure the length of a line segment.
b. A triangle has four sides, four angles and four
vertices.
c. A quadrilateral has four sides, four angles and
four vertices.
d. A circle has no vertices.
e. Every side of a square is equal.
f. Every side of a rectangle is equal.

8. Identify whether the given figure are triangle, rectangle or square.

106 Oasis School Mathematics Book-3

Project work

Prepare different shapes using the pieces of paper having different
shapes (triangle, quadrilateral, circle, etc.)
Trace different shapes (triangle, rectangle, square, circle, etc.)
Cut these pieces.

Paste these on the chart paper to make the following figures:

Make the figure of your imagination by pasting these objects.

Oasis School Mathematics Book-3 107

Objective Questions

Colour the correct alternative:
1. The given figure is a ..........................

point line segment line

2. A .......................... is endless.

point line segment line

3. The name of the angle in the given figure is .......................... A

∠ABC ∠BAC ∠ACB

4. How many sides are there in a triangle? B
24
3

5. How many arms are there in an angle? 3
12

6. I have 4 sides, 4 angles and 4 vertices. I am a ..........................

triangle circle quadrilateral

7. I am a round plane figure. I have no vertices. Who am I?

Triangle Quadrilateral Circle

108 Oasis School Mathematics Book-3

Unit Evaluation Full Marks : 30

1. Name the given figures: P 4
X
A S
Q
Q

P BY ZR

2. Measure the length of each side of the given figure: 4
2
A B AB = cm 2

BC = cm

CD = cm

D C AD = cm

3. Write the name of the angle, its vertex and arms:
A Angle :

Vertex :

B C Arms : and

4. Write (L) for the larger angle and (S) for the smaller one:
a. b.

Oasis School Mathematics Book-3 109

5. Identify whether the given angles are right angle or not. Tick  if it

is a right angle and cross (×) if it is not. 2

6. Identify whether the given figures are square or rectangle. Write 'S'

if its is a square and 'R' for a rectangle. 2

7. Name the given figure and write sides and angles: 5
P Q The name of the figure 4

Sides , , and

SR Angles , , ,
sides.
and

8. Fill in the blanks:

a. A triangle has angles and

b. A quadrilateral has angles and sides.

9. Write (T) for true statements and (F) for false ones: 3
a. A point has no length, breadth and height.
b. A triangle has four vertices.
c. A circle has a centre and radius.

10. With the help of a ruler and a pencil, draw lines of the given length: 2

AB = 4.5 cm PQ = 6 cm

110 Oasis School Mathematics Book-3

Basic Operation
on Mathematics

Contents
• Addition
• Subtraction
• Multiplication
• Division

Oasis School Mathematics Book-3 111

Addition

Look and learn.

Basic preparation for addition 7 + ......

Find different ways to get the given number:

7 + 1 2 + 6 4 + ......

6+2 3+5 3 + ...... 9 8 + ......
5+3 2 + ......
4+4 6 + ......
1 + ......
6 + ......

2 + ...... 10 ......+ 5
......+ 4
......+ 3

6 + ...... 9 + ...... 8 + ...... 9 + ......

......+ 7 12 ......+ 3 ......+ 6 11 2 + ......

8 + ...... 4 + ...... 7 + ...... ......+ 1

Add (Review) 7+8+1= 4+3+8=
2+9+6=
7+8= 5+5+5=
6+3+9=
6+4= 4+5+6= 7+1+9=
3+8+7=
3+7= 3+2+1=

4+9= 9+1+5=

5+9= 2+9+3=

6+9= 1+2+8=

112 Oasis School Mathematics Book-3

Addition of two Numbers in Different ways:

Look and learn.

Method I Add : 23 + 64 It’s interesting.

23 64

20 + 3 + 60 + 4 Break up both the numbers.
20 + 60 = 80 Add Tens.
3 + 4 = 7 Add Ones
80 + 7 = 87 Add the sum.

52 + 43 14 + 43 64 + 21

50 + 2 40 + 3
50 + 40 = 90
2+3=5
90 + 5 = 95

TO THE TEACHER:
> Ask many other questions to the students and tell them to answer orally.

Method II 52 + 20 = 72
Look and learn. 72 + 4 = 76
Add: 52 + 24
Break up only one number .

52 + 24 Break up only one number.
20 + 4 Add 20 to 52.
Add 4 to 72.
52 + 20 = 72
72 + 4 = 76

Oasis School Mathematics Book-3 113

Add mentally (Using any one of the above methods):

23 + 26 = 27 + 32 = 65 + 23 = 15 + 22 =

46 + 23 = 34 + 24 = 86 + 12 = 36 + 12 =

Method III I understand ! 18
Look and learn. is 2 less than 20.

Add: 19 + 37 Add: 25 + 18
20 + 37 = 57 25 + 20 = 45
57 - 1 = 56 45 - 2 = 43

Add 37 and 20 and subtract 1. Add 25 and 20 and subtract 2.

Add mentally: 23 + 19 = 46 + 29 =
46 + 18 = 23 + 28 =
19 + 18 = 24 + 19 = 54 + 39 =
37 + 9 = 45 + 29 = 35 + 28 =
43 + 19 =
53 + 38 =

114 Oasis School Mathematics Book-3

Addition of 3 Numbers

Add two numbers to make 10 and add the third number.

4 + 7 + 6 = 10 + 7 = 17

3 + 8 + 7 = + = 9+
4 + 7 + 6 = + = 8+ 1+
8 + 5 + 2 = + =
6 + 8 + 4 = + = 7 + 10 2 +
3 + 8 + 7 = + = 6+ 3+

5+ 4+

2 + 6 + 4 = + =

Add two numbers to make 20 and add the third number.

4 + 8 + 16 = 20 + 8 = 28

6 + 17 + 3 = + =

15 + 3 + 5 = + = 18 + 919++ 11 +
17 + 20 12 +
17 + 8 + 3 = + = 16 + 13 +
15 +
14 + 9 + 6 = + = 14 +

12 + 3 + 8 = + =

11 + 9 + 7 = + =

Oasis School Mathematics Book-3 115

Addition without Carryover

Look and learn.

486 Add ones : 6 + 2 = 8
+3 1 2 Add tens : 8 + 1 = 9
798 Add hundreds: 4 + 3 = 7

Add: 6 3 3 5 5 0 2 1
+ 2 1 + 2 4 + 2 6 + 3 2
3 5 + 2 1 + 3 6
+ 4 2

4 6 5 2 2 5 3 3 2 1 3 2 6
+ 2 3 + 2 6 + 1 2 4 + 6 3 7 + 3 5 1
+ 3 0 + 2 1

7 2 9 5 8 0 1 1 0 2 1 4 2 3 1
+ 2 7 0 + 3 1 9 + 3 2 1 + 5 4 1 + 3 2 2
+ 1 6 2 + 2 1 0 + 1 4 2

1 9 2 1 6 4 3 3 3 6 2 1 2 2 2
+ 2 0 1 + 3 1 1 + 1 2 0 + 1 4 7 + 3 3 3
+ 3 0 2 + 2 2 2 + 1 4 0 + 2 3 0 + 4 1 2

116 Oasis School Mathematics Book-3

Addition with Carry Over

Look and learn.

1 8 Ones + 6 Ones = 14 Ones
4 8
+ 3 6 = 1 Tens + 4 Ones,
8 4
carry over 1 Tens 1 + 4 + 3 = 8

Add:

3 7 5 8 2 8 4 6 5 7
2 7 + 5 6 + 2 3 + 4 7 + 2 6 + 2 4
+ 3 7


2 3 4 5 6 5 3 6 5 4 6 8
+ 6 5 + 3 7 + 3 4 + 2 5 + 2 3 + 3 4
+ 4 7 + 3 2 + 4 4 + 3 4 + 3 6 + 1 6

5 3 2 4 5 6 2 7 5 4 8 5 7 2
+ 2 7 9 + 3 6 8 + 3 7 5 + 3 7 5 + 3 1 4
+ 5 6 5

4 3 6 2 5 6 2 6 3 4 8 2 5 6 2
+ 1 7 5 + 3 4 5 + 3 4 4 + 5 6 3 + 7 8
+ 3 2 1 + 2 3 5 + 4 5 4 + 2 1 7 + 2 5 3

Oasis School Mathematics Book-3 117

Addition of Four-digit Numbers

Look and learn.

3 5 2 1 Add Ones : 1 + 7 = 8 I understand it.
+ 6 2 3 7 Add Tens : 2 + 3 = 5
Add Hundreds : 5 + 2 = 7
9 7 5 8 Add Thousands : 3 + 6 = 9

Add:

2 5 6 3 3 6 5 2 4 2 6 5 2 3 4 5
+ 3 4 2 1 + 3 2 3 0 + 3 2 1 4 + 1 2 3 4

4 5 2 1 4 6 4 2 6 2 5 4 4 3 2 6
+ 3 2 5 4 + 1 2 3 4 + 2 3 0 2 + 5 2 0 0

2 5 6 2 2 3 5 2 4 6 2 5 3 2 6 5
+ 3 2 1 + 5 3 2 + 2 3 4 + 4 3 4

3 2 1 4 5 2 3 1 2 3 5 2 6 2 3 5
+ 2 3 1 0 + 1 4 0 2 + 2 3 4 1 + 1 2 2 2
+ 2 0 5 2 + 3 2 1 3 + 4 0 0 4 + 2 0 4 0

2 5 4 3 1 4 3 2 3 2 1 4 3 2 3 4
+ 1 0 3 2 + 2 3 4 2 + 3 2 5 + 3 2 4
+ 4 1 3 + 2 1 0 + 4 1 4 0 + 4 2 2 1

118 Oasis School Mathematics Book-3

Addition of Four digit Numbers (with carry over):

Look and learn. Add Ones: 7 + 4 = 11 Ones
= 1 Tens + 1 Ones, carry over 1 Tens
1 1 1 Add Tens : 6 + 7 + 1 = 14 Tens
5 4 6 7 = 1 Hundreds + 4 Tens, carry
+ 1 5 7 4
7 0 4 1 over 1 Hundreds
Add Hundreds: 1 + 4 + 5 = 10 Hundreds
1 Thousands + 0 Hundreds,

carry over 1 Thousands
Add Thousands: 1 + 5 + 1 = 7

Add the following:

Th H T O Th H T O Th H T O Th H T O

4 3 6 5 7 3 6 4 6 3 8 7 2 8 6 4
+ 3 7 5 7 + 1 8 6 8 + 4 8 5 6 + 3 7 6 7

Th H T O Th H T O Th H T O Th H T O

3 7 2 4 2 5 3 9 6 5 3 2 5 8 3 7
+ 4 5 8 7 + 3 1 8 2 + 2 8 1 9 + 3 6 2 9

Th H T O Th H T O Th H T O Th H T O

7 6 3 2 5 6 0 8 3 8 6 4 2 4 5 6
+ 2 8 1 5 + 3 7 1 4 + 4 7 7 6 + 3 7 1 7

Th H T O Th H T O Th H T O Th H T O

5 3 6 7 2 4 6 8 3 5 6 7 4 5 6 3
+ 2 4 8 6 + 8 7 4 + 6 7 5 + 2 3 6 5
+ 1 2 3 7

Oasis School Mathematics Book-3 119

Addition of more than Four digit Numbers:

Add: I know this is also the
same as addition of 4
1 1 1
5 4 6 3 2 digit numbers.
+ 1 5 7 8 3
7 0 4 1 5

2 6 4 9 3

+ 2 5 6 3 7


5 4 1 2 6 6 2 8 2 7 5 4 9 2 3
+ 3 7 4 9 + 2 9 3 0 4 + 1 7 2 6 2

Add:
5 2 1 8 7 6 5 2 8 4
8 4 3 2 1 + 1 5 6 3 7 + 3 0 9 3 6
+ 9 2 0 6

5 6 2 9 2 3 1 5 4 6 3 0 7 5 4
+ 4 3 7 6 + 2 3 4 8 2 + 8 7 6 2 1
+ 1 6 5 + 1 5 7 6 4 + 5 1 2
+ 4 2 + 6 4 2 1

4 1 2 5 6 5 6 7 1 2 5 4 3 7 6
+ 7 2 8 4 + 3 7 2 4 6 + 6 2 5 2 0
+ 2 1 4 8 + 9 4 5 3 + 4 3 4 1

120 Oasis School Mathematics Book-3

Addition in our Daily Life

Look and learn.

The male population of a village is 3478 and the female population is
4286. Find the total population of the village.

Male population = 3 4 7 8
Female population = + 4 2 8 6

Total population = 7 7 6 4

1. There are 2678 apples in
a tree and 3723 apples
in another tree. Find the
total number of apples.

2. Lakpa has Rs. 3428, Bablu
has Rs. 2326 and Chameli
has Rs. 1832. Find the total
amount of money they have.

3. A man spent Rs. 2364 to buy
a watch, Rs. 2287 to buy a
radio and Rs. 27920 to buy
a television. Find the total
amount he spent.

4. In a school, there are 3478
students in primary level,
2375 students in lower
secondary level and 1220
students in secondary level.
How many students are
there altogether?

Oasis School Mathematics Book-3 121

5. A man earns Rs. 5647 in
the month of Baisakh, Rs.
6842 in the month of Jestha
and Rs. 1342 in the month
of Ashad. What is his total
income in these three
months?

6. A shopkeeper sold 2350
kg of rice in the month of
January, 3268 kg of rice in
the month of February and
1236 kg of rice in the month
of March. How much rice
did he sell in these three
months?

7. A school library had 5637
old books and 1258 new
books were brought. Find
the total number of books
in the library.

Solve the following problems in your copy:
1. The male and the female population of a town are 32648 and 46476

respectively. Find the total population of the town.
2. On their holiday, a family spent Rs. 12379 on food, Rs 16742 on lodging

and Rs 6547 on sight seeing. How much did their holiday cost them?
3. Saleem earned Rs. 40368 from his business and Rs 16342 from his

salary. Find his total income.
4. Suntali deposited Rs. 65375 on Sunday, Rs 21674 on Monday and Rs

12383 on Tuesday. How much did she deposit in all?
5. Saila Dai bought motorcycle for Rs 75364 and a laptop for Rs 56486.

How much did he spend to buy them?

122 Oasis School Mathematics Book-3

Subtraction

Basic preparation for Subtraction

Review

Find different ways to get the given number:

Subtract: 13 – 5 = 9
12 – 5 = 13 – 6 =
12 – 6 = 13 – 7 = 14 – 7 =
12 – 7 = 13 – 8 = 14 – 8 =
12 – 8 = 13 – 9 = 14 – 9 =
12 – 9 = 14 – 5 = 15 – 5 =
12 – 4 = 14 – 6 = 15 – 6 =
12 – 2 = 15 – 7 =
15 – 8 =

Oasis School Mathematics Book-3 123

Different ways of Subtraction: It’s interesting.

Look and learn. Method I
Subtract: 46 – 22

46 - 22 Break up the second number Subtract quickly:
20 2 60 – 20 = ........
46 - 20 = 26 Subtract both of them from the 64 – 30 = ........
26 - 2 = 24 first number. 56 – 40 = ........
58 – 20 = ........
Subtract as above: 85 – 30 = ........
89 – 40 = ........
96 – 20 = ........
94 – 10 = ........
92 – 80 = ........

Subtract mentally:

65 - 36 = 54 - 23 = 46 - 24 = 76 - 43 =

62 - 25 = 83 - 24 = 95 - 24 = 84 - 51 =

Method II Subtract: 4 + 10 + 2 = 16
Look and learn. 63 - 42
Subtract : 52 - 36

36 to 40 is 4 40 - 36 = 4 46 - 28
40 to 50 is 10 50 - 40 = 10 62 - 36
50 to 52 is 2 52 - 50 = 2
4 + 10 + 2 = 16
\52 - 36 = 16

Subtract mentally:

26 - 17 = 44 - 32 = 65 - 46 = 48 - 26 =

124 Oasis School Mathematics Book-3

Subtraction without Borrowing:

Look and learn.

Subtract: Subtract Ones: 7 – 4 = 3
597 Subtract Tens : 9 – 3 = 6
Subtract Hundreds : 5 – 2 = 3
–2 3 4

363

Subtract: (without borrowing)

5 6 7 8 6 7 5 8 9 8 4 6
- 3 2 1 - 3 2 0 - 2 3 6 - 2 3 5

8 6 4 5 6 7 9 2 7 6 5 2
- 3 2 1 - 2 3 4 - 1 2 4 - 5 1 2

6 3 4 5 9 8 6 2 4 9 5 6
- 2 3 2 - 2 2 3 - 1 0 3 - 2 1 4

5 5 5 8 9 7 6 4 1 8 9 6
- 3 2 3 - 1 2 3 - 1 2 0 - 5 4 2

9 9 9 8 8 8 7 7 7 6 6 6
- 4 5 3 - 6 4 5 - 3 0 3 - 3 5 0

5 5 5 7 1 9 3 1 2 9 6 1
- 1 4 0 - 6 0 4 - 2 0 1 - 7 1 1

Oasis School Mathematics Book-3 125

Subtraction (With Borrowing)

Look and learn. Subtract Ones:
3 < 8, so 8 can not be subtracted from 3.
Subtract: Borrow 1 ten from 2 tens.
1 ten + 3 ones = 13 ones
7 11 13 13 ones – 8 ones = 5 ones.

823 Subtract Tens:
–4 6 8 As 1 ten out of 2 tens is borrowed, 1 ten left.
1 < 6, borrow 1 hundred form 8 hundreds.
355 1 hundred + 1 ten = 11 tens
11 tens – 6 tens = 5 tens.

Subtract hundreds:
As 1 hundred out of 8 is borrowed, 7
hundreds left.
7 hundreds – 4 hundreds left = 3 hundreds.

Subtract: (with borrowing)

12 12 6 7 8 5 4 2 3 7 6
- 4 6 9 - 3 7 6 - 2 8 5
5 3 2
- 1 5 8
3 7 4

9 8 2 8 2 3 9 1 8 6 2 3
- 5 7 6 - 3 8 5 - 6 2 3 - 2 4 6

3 6 4 5 7 2 9 2 3 8 6 2
- 1 7 6 - 2 8 4 - 6 8 4 - 3 5 6

126 Oasis School Mathematics Book-3

Subtraction of 4 digit Numbers (Without Borrowing)

Look and learn.

5 6 2 5 Subtract Ones: 5-4=1
- 3 2 1 4 Subtract Tens : 2 - 1 = 1
2 4 1 1 Subtract Hundreds : 6 - 2 = 4
Subtract: Subtract Thousands : 5 - 3 = 2

4 6 2 5 5 4 2 7 6 3 7 4 5 4 6 9
- 2 3 1 4
- 2 3 0 3 - 1 2 2 4 - 2 3 4 1

7 6 9 2 8 4 5 7 7 6 7 8 3 9 6 4
- 1 4 3 2 - 3 3 3 3 - 1 2 6 0 - 1 8 4 2

3 7 8 4 8 4 3 7 5 4 6 8 7 8 6 9
- 2 6 3 - 3 2 6 - 3 4 8 - 4 7

Arrange the given numbers in columns of Thousands, Hundreds,
Tens, Ones and subtract in your copy:

5632 - 4201 4531 - 3120 3789 - 1721

5782 - 2671 8259 - 3123 5486 - 3254

Solve the given questions in your copy:

Subtract 3715 from 8926. Arrange the given numbers in
Subtract 512 from 2664. columns keeping larger on top
Subtract 1234 from 8256. and subtract.

Subtract 2014 from 6378.

Oasis School Mathematics Book-3 127

Subtraction of 4-digit Numbers (With Borrowing)

Borrowing once

Look and learn. 2<7
- Borrow one from 8 Tens leaving

7 12 7 Tens in the Tens place.
3 7 8 2 In Ones place,
- 1 Tens + 2 Ones = 12 Ones

- 1 6 2 7 Subtract Ones:

2 1 5 5 12 - 7 = 5
- Subtract Tens: 7 - 2 = 5

- Subtract Hundreds: 7 - 6 = 1

- Subtract Thousands: 3 - 1 = 2

Subtract:

7 4 8 2 8 5 3 7 5 7 6 2 6 3 6 4
- 2 3 4 8 - 1 2 2 9 - 2 1 5 8 - 2 1 4 6

5 7 6 4 5 7 6 3 5 4 9 2 6 4 3 7
- 2 3 2 9 - 2 3 4 8 - 1 3 2 6 - 2 4 1 9

6 8 3 2 5 7 6 3 5 4 9 2 6 4 3 7
- 5 7 1 6 - 2 3 4 8 - 1 3 2 6 - 2 4 1 9

6 8 3 5 5 4 6 2 6 8 3 2 7 6 5 4
- 5 4 1 7 - 2 1 3 7 - 5 4 1 9 - 1 2 3 7

128 Oasis School Mathematics Book-3

Subtraction of 4 digit Numbers (With Borrowing,
Borrowing more than once)

Look and learn.

2 12 Subtract the Ones:
8 8 3 2 2 < 4, borrow 1 Tens from 3 Tens leaving 2 Tens
- 6 9 6 4 1 Tens + 2 Ones = 12 Ones
8 (12 - 4) = 8 Ones

7 12 12 Subtract the Tens:
8 8 3 2 As 1 Tens out of 3 is borrowed.
- 6 9 6 4 2 Tens left.
6 8 2 < 6, borrow 1 Hundreds from 8 Hundreds
1 Hundreds + 2 Tens = 12 Tens
12 Tens - 6 Tens = 6 Tens

7 17 12 12 Subtract the Hundreds:
8 8 3 2 As 1 Hundreds out of 8 is borrowed.
- 6 9 6 4 7 Hundreds left.
8 6 8 7 < 9, borrow 1 Thousands
1 Thousands + 7 Hundreds = 17 Hundreds
7 17 12 12 17 - 9 = 8 Hundreds
8 8 3 2
- 6 9 6 4 Subtract the Thousands:
1 8 6 8 As 1 Thousands out of 8 is borrowed
Subtract: 7 Thousands left.
7 - 6 = 1 Thousands

3 7 2 5 2 4 8 6 8 6 4 2 7 4 3 5
- 1 2 6 7 - 1 3 9 8 - 6 2 8 6 - 2 3 8 9

Oasis School Mathematics Book-3 129

3 7 5 2 7 4 3 2 8 5 6 2 6 7 2 0
- 2 3 7 6 - 4 3 8 5 - 1 3 9 6 - 1 4 6 8

5 3 8 4 6 2 9 3 7 1 3 4 5 0 8 2
- 2 6 1 5 - 4 5 1 6 - 2 6 0 8 - 4 3 6 8

4 7 3 2 8 3 5 4 4 5 6 4 5 0 7 0
- 1 9 6 4 - 2 9 6 5 - 1 6 7 6 - 3 1 9 2

4 1 7 2 5 0 8 0 4 5 6 0 5 0 0 0
- 1 4 7 8 - 1 9 7 8 - 1 7 9 8 - 2 4 9 6

4 6 7 5 8 2 6 4 7 6 5 0 1 5 8 7
- 9 8 6 - 8 7 2 - 9 8 6 - 9 9 9

Arrange the given numbers in columns of Thousands, Hundreds,
Tens and Ones and subtract in your copy.

5263 - 3049 8462 - 3226 5475 - 1328 4321 - 2976

6126 - 3978 5634 - 2876 9832 - 5467 7854 - 6286

6935 - 3568 6837 - 5362 7093 - 5681 8164 - 3728

Solve the given questions in your copy.

Subtract 4206 from 7532. Subtract 4632 from 8251.

Subtract 1169 from 5248. Subtract 3126 from 3925.

Subtract 2496 from 4630. Subtract 1782 from 4000.

130 Oasis School Mathematics Book-3

Checking Subtraction by Addition:

Look and learn.

9 3 6 2 Larger number 4 3 4 2 Difference
- 5 0 2 0 Smaller number + 5 0 2 0 Smaller number
4 3 4 2 Difference 9 3 6 2 Larger number

Larger number - Smaller number = Difference

Difference + Smaller number = Larger number

Subtract and check by addition:

Checking Checking
1 2 6 3
3 7 8 5 + 2 5 2 2 2 8 6 5
- 1 2 6 3 = 3 7 8 5 - 1 6 8 9
2 5 2 2

5 6 2 3 3 9 2 4
- 1 2 3 5 - 1 8 6 7

6 3 9 5 4 8 0 6
- 5 0 8 6 - 3 2 1 7

7 8 0 1 6 6 2 1
- 5 2 6 3 - 4 5 3 9

Oasis School Mathematics Book-3 131

Subtraction of 5-digit Numbers

Look and learn.

Process of subtraction of 5-digit numbers is the same as the subtraction
of 4-digit numbers.

Start subtracting from Ones and go up to Ten Thousands.

Subtract: Subtract Ones : 4-1=3
Subtract Tens : 8-4=4
5 6 7 8 4 Subtract Hundreds : 7-5=2

- 2 3 5 4 1

3 3 2 4 3 Subtract Thousands : 6 - 3 = 3
Subtract Ten thousands : 5 - 2 = 3
Subtract:

8 3 7 4 2 5 7 6 4 2 6 4 3 2 1 8 6 1 2 5

- 6 2 1 3 1 - 3 0 3 1 0 - 3 3 2 1 0 - 3 6 0 2 1

7 6 5 4 3 5 7 3 2 0 5 6 3 2 9 4 6 5 4 2
- 2 3 4 0 1 - 2 4 1 1 0 - 1 5 1 0 6 - 1 6 2 1 0

Subtraction by borrowing in 5-digit is also the same as the subtraction
in 4-digit.

Subtract by borrowing:

5 3 1 6 4 6 4 1 7 4 4 5 8 1 3 5 1 7 0 4
- 2 1 5 3 7 - 2 6 0 8 6 - 2 7 6 3 4 - 3 2 8 1 7

2 3 6 4 1 5 4 1 8 6 6 2 0 9 3 7 0 0 1 5
- 1 2 5 8 3 - 3 2 1 9 4 - 4 1 3 2 6 - 5 1 6 2 7

132 Oasis School Mathematics Book-3

Subtraction in our Daily Life

Look and learn.

In the questions, if there is How many more? How many left ? subtraction
sign is used. Lets be clear with given example.
Suyog had 5237 marbles. He sold 2852. How many marbles are left with him?

4 11 13

Number of marbles Suyog had = 5 2 3 7 Read the question
properly and decide what
Number of marbles he sold - 2 8 5 2 you have to do addition or
subtraction
Number of marbles left = 2 3 8 5

Hence, Suyog has 2385 marbles left with him.

Solve the following problems in your copy:

1. Subtract 6327 from 8265.
2. Subtract 21375 from 52874.
3. Take away 3728 from 7262.
4. A shopkeeper bought 4238 eggs. He sold 1963 of them in a day.

How many eggs were left unsold?

5. The total population of Gorkha bazar is 2834. Out of them, 1468 are
males. Find the number of females.

6. Prapti earned Rs 7324 in November. She saved Rs 1864. How much
did she spend during the month?

7. The population of a village is 1837. If 1168 of the villagers have
attended school, how many of them have not gone to school?

8. Ayuna has Rs 4862. He wants to buy a mobile costing Rs 9628. How
much more money does he require to buy the mobile?

9. Arpan earns Rs 5328 and spends Rs 2492 in a month. How much
money does he save in a month?

10. Two cricketers Subash and Sharad scored 14262 and 11956 runs
respectively in ODI cricket. How many more runs did Subash score
than Sharad?

Oasis School Mathematics Book-3 133

Addition and Subtraction together

Look and learn.

Let's be clear from the given example:

Simplify: 2321 + 4825 - 3516

1 Add the numbers with the + sign or no sign
before them.
2 3 2 1
Here, 2321 + 4825
+ 4 8 2 5

7 1 4 6

6 11 From the sum, subtract the number having
- sign.
7 1 4 6
Here, subtract 3516 from the sum.
- 3 5 1 6

3 6 3 0

2321 + 4825 - 3516 = 3630
Let's see one more example:

Simplify: 1234 - 567 - 832 + 1482

1 Add the numbers with + sign or
1 2 3 4 no sign before them.

+ 1 4 8 2 Here, 1234 and 1482

2 7 1 6

5 6 7 Add the numbers with - sign.
+ 8 3 2 Here 567 and 832
1 3 9 9

6 10 16 Subtract the smaller number
from the bigger one.
2 7 1 6
- 1 3 9 9 \ 1234 - 567 - 832 + 1482 = 1317
1 3 1 7

134 Oasis School Mathematics Book-3

Simplify: 5421 + 2314 – 6351
5623 + 2132 – 3218

5623 + 2132 – 3218 = 5421 + 2314 – 6351 =
1563 – 3084 + 6729 - 2168 4612 - 508 - 1732 + 642

1563 – 3084 + 6729 - 2168 = 4612 - 508 - 1732 + 642 =

Solve the following problems in your copy:

a. 2684 - 1032 + 4519 b. 5462 - 607 + 342

c. 3219 - 1052 - 256 d. 4378 - 1264 - 2135

e. 6432 - 1032 + 1467 - 842 f. 5914 - 1932 - 2964 + 2314

Oasis School Mathematics Book-3 135

Worksheet Here are the list of top 5 highest peak of Nepal.

Mt. Everest Mt. Kanchanjanga Mt. Lhotse
8,848 m. 8,586 m. 8,516 m.

Mt. Makalu Mt. Cho Oyu Map
8,485 m. 8,188 m.

Arrange the height of the mountains in the descending order.

By how much height of Mt. Everest is more than
the height of Mt. Kanchenjunga?

By how much height of Mt. Cho oyu is less than
the height of Mt. Makalu?

By how much height of Mt. Everest is more than
the height of Mt. Lhotse?

136 Oasis School Mathematics Book-3

Objective Questions

Choose the correct alternative:
1. The sum of 1500 and 2500 is equal to

4000 7000 5000

2. If 1800 is added to 1200 then the result is equal to

4000 6000 3000

3. If 4700 is increased by 1300 the result is equal to

5000 6000 3400

4. The difference of 7500 and 2500 is equal to

4000 5000 10,000

5. 9500 is greater than 7500 by

2000 3000 17,000

6. Find the sum of 6000 and 9000 and subtract 3000 from the sum. The
correct mathematical sentence of this statement is

6000 + 9000 + 3000 6000 – 9000 + 3000 6000 + 9000 – 3000

7. Sagar has Rs 2465, Ashrika has Rs 2025 and Kritika has Rs 3650.
How much money do they have altogether?

The mathematical statement of this question is

2465 + 2025 + 3650 2465 + 2025 – 3650 2465 – 2025 + 3650

8. Dipsha has Rs 4700 and Rupsha has Rs 3000. How much more money
has Dipsha than Rupsha?

4700 – 3000 4700 + 3000 3000 – 4700

9. 4800 + 2000 – 3000 is equal to 3800

5800 4800 Oasis School Mathematics Book-3 137

Unit Evaluation Full Marks : 20

1. Add: 4
4 3 6 4
+ 1 7 8 6 8 2 9 8
+ 2 7 6
3 7 2 4
+ 1 2 6 8 1 7 8 2
+ 1 5 2 3 + 3 9 5
+ 6 4 8 6

2. Subtract: 5 3 2 6 3 6 4 4
- 1 5 8 - 2 1 4 6
5 8 9 4 6 8 2
- 3 2 1 - 3 2 5 7

3. The male and female 2
population of a village are 2
1682 and 1898 respectively.
Find the total population of
the village.
∴ The total population of

village =

4. A shopkeeper bought
4238 eggs. He sold 1962 of
them in a day. How many
eggs were left unsold?

∴ eggs were left unsold.

138 Oasis School Mathematics Book-3

5. In a school, out of 1782 2
students, 1293 are boys.
How many are girls?

∴ The no. of girls =

6. Solve the given questions: 2
Subtract 3715 from 8926.
Take 385 out of 4672.

7. Simplify: 4
2352 + 2124 - 1623
2684 + 307 - 842

Oasis School Mathematics Book-3 139

Multiplication

Multiplication as repeated addition

Look and learn.

How many flowers in all?

2+2+2+2 =8
4 twos are 8.
4×2=8

How many balls in all?

4 + 4 + 4 + 4 + 4 + 4 = 24 Addition of 4, 6 times
6 fours are 24.
6 × 4 = 24
Complete the following table:

3 + 3 + 3 + 3 + 3 + 3 = 18 6 threes are 18. 6 × 3 = 18

4 + 4 + 4 + 4 = 16
5 + 5 + 5 = 15
8 + 8 + 8 + 8 + 8 + 8 + 8 = 56
9 + 9 + 9 + 9 = 36
6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 + 6 = 54

Remember !

Any number multiplied by 0 is always 0.
3 × 0 = 0, 0 × 6 = 0
Any number multiplied by 1 is the number itself.
5 × 1 = 5, 1 × 6 = 6

140 Oasis School Mathematics Book-3

Multiplication table from 2 to 5

Multiply the number in the centre by the given numbers:

Multiplication table from 6 to 10

Oasis School Mathematics Book-3 141

Find the products:

7×4= 8×5= 9×3= 10 × 6 =
6×6= 6×9 =
6×3= 6×5= 8×6= 8×9 =
9×8= 9×9 =
7×5= 7×6=

9×4= 9 ×7 =

Write the missing numbers in the boxes:

4 × = 32 6 × = 42 8 × = 48 9 × = 27
= 49 7 × = 56
5 × = 45 5 × = 35 7 ×

× 6 = 36 × 5 = 40 × 4 = 28 × 5 = 30
× 8 = 72 × 7 = 63 × 6 = 54 × 3 = 24

Multiplication table from 11 to 12

Find the product of:

11 × 6 = 12 × 7 = 11 × 5 = 12 × 4 =

11 × 8 = 11 × 4 = 12 × 5 = 12 × 6 =

Write the missing numbers in the boxes:

× 3 = 33 × 4 = 48 × 5 = 55 × 7 = 77

11 × = 22 12 × = 36 12 × = 84 12 × = 96

142 Oasis School Mathematics Book-3

Multiplication of 2-digit and 3-digit Numbers by a Single digit
Number

Look and learn. I learnt this in class two.

3 2 Multiply Ones by 3, 2 × 3 = 6 2 1
× 3 Multiply Tens by 3, 3 × 3 = 9 × 3
9 6
4 2 3 3 4 1
Multiply: × 2 × 3 × 2

2 3 3 2
× 3 × 2

3 1 5 4 6 3 5 2 6 4 5 3
× 3 × 2 × 3 × 3 × 2 × 2

Multiplication of 3-digit Numbers by a Single digit Number

1 2 3 Multiply Ones 3 × 3 = 9
× 3 Multiply Tens 2 × 3 = 6
3 6 9 Multiply Hundreds 1 × 3 = 3

Multiply: 3 0 2 3 2 1 3 3 3 3 2 0 3 2 2
× 3 × 3 × 2 × 2 × 3
3 0 1
× 2

1 2 3 3 0 4 1 2 2 2 2 2 3 2 1 3 2 2
× 3 × 2 × 4 × 3 × 3 × 3

Oasis School Mathematics Book-3 143

Multiplication of 2-digit and 3-digit Numbers by a Single digit
Number (with carry-over)

Look and learn.

2 Multiply Ones: 6 × 4 = 24
5 6 Write 4 at the bottom, carry over 2
× 4 Multiply Tens: 5 × 4 = 20
2 2 4 Add carry over 2, 20 + 2 = 22
Write 22 at the bottom before 4.

Multiply: 3 6 2 6 4 8 5 6 6 2
4 3 × 4 × 3 × 4 × 6 × 7
× 5

7 8 8 2 9 3 5 4 3 7 6 6 7 7
× 4 × 6 × 7 × 5 × 7 × 6 × 7

Multiplication of 3-digit numbers by a single digit number (with carry-over)

33 Multiply Ones: 7 × 5 = 35. Write 5 at the bottom, carry
over 3 tens
2 6 7
× 5 Multiply tens: 6 × 5 = 30. Add carry over 3, 30 + 3 = 33.
1 3 3 5 Write 3 at the bottom, carry over 3 Hundreds

Multiply Hundreds: 2 × 5 = 10. Add carry over 3,
10 + 3 = 13. Write 13 at the bottom.

Multiply:

2 3 6 5 2 4 3 3 6 2 5 8 3 4 6
× 5 × 4 × 5 × 7 × 7

5 0 7 3 1 6 5 6 3 6 7 2 5 7 7
× 4 × 8 × 5 × 4 × 6

144 Oasis School Mathematics Book-3

Multiplication of Numbers by Tens, Hundreds and Thousands

Multiplication by 10's

Look and learn.

6 × 10 = 60 Multiply 6 and 1 and write one zero on the right.
3 × 40 = 120 Multiply 3 and 4 and write one zero on the right.

Multiplication by 100's

5 × 100 = 500 Multiply 5 and 1 and write 2 zeros on the right.
6 × 300 = 1800
5 × 100 6 × 300

500 1800

Multiplication by 1000's

8 × 3 000 = 24000 Multiply 8 and 3 8 × 3000

Write 3 zeros on the right 24000
Multiply:

4 × 20 = 5 × 30 = 3 × 20 = 2 × 18 =

6 × 40 = 7 × 30 = 6 × 50 = 5 × 16 =

8 × 10 = 3 × 40 = 8 × 30 = 8 × 50 =

Multiply:

3 × 100 = 4 × 200 = 5 × 300 = 4 × 300 =

6 × 400 = 7 × 100 = 3 × 900 = 7 × 600 =

9 × 300 = 8 × 600 = 7 × 700 = 6 × 900 =

Multiply: 7 × 2000 = 7 × 4000 = 4 × 3000 =
6 × 1000 =

5 × 9000 = 5 × 3000 = 3 × 6000 = 6 × 8000 =

Oasis School Mathematics Book-3 145

Multiplication of two digit Numbers by two digit Numbers

Look and learn.

Multiply: 46 × 24

Break 24 into 20 + 4. Multiply 46 by 4 Alternative method
4 6
24 = 20 + 4 4 6 Multiply by 4
× 4 × 2 4 Multiply by 20
Multiply 46 by 20. 1 8 4 1 8 4 Add
4 6 + 9 2 0
× 2 0 Add the products
1 8 4 1 1 0 4

9 2 0 + 9 2 0

1 1 0 4

Multiply:

4 2 6 4 6 7 8 6 5 6
× 3 4 × 2 1 × 3 2 × 2 3 × 4 2

8 2 7 2 6 7 5 4 4 8
× 2 5 × 1 8 × 1 7 × 2 3 × 1 5

146 Oasis School Mathematics Book-3

Multiplication of three digit Numbers by two digit Numbers

Look and learn.

325 × 34 34 = 30 + 4 break 34 3 2 5 Multiply 325 by 30.
Multiply 325 by 4. × 3 0 Add the products.
3 2 5 9 7 5 0
× 4
1 3 0 0 1 3 0 0
+ 9 7 5 0
1 1 0 5 0

Alternative method:

3 2 5 I understand it
× 3 4
1 3 0 0 Multiply by 4
+ 9 7 5 0 Multiply by 30
1 1 0 5 0 Add

Multiply:

2 7 6 5 3 2 3 1 6 4 2 6

× 2 4 × 4 1 × 5 2 × 5 1

5 7 6 6 2 4 8 3 7 5 2 0
× 3 4 × 6 2 × 2 6 × 2 7

Oasis School Mathematics Book-3 147

Multiplication of three digit Numbers by three digit Numbers

Look and learn.

Multiply : 425 × 163 4 2 5 Add
× 1 6 3 products
163 = 100 + 60 + 3 Break down 163 1 2 7 5
2 5 5 0 0
Multiply 425 by 3 Multiply 425 by 60 Multiply 425 by 100 4 2 5 0 0
6 9 2 7 5
4 2 5 4 2 5 4 2 5
× 3 × 6 0 × 1 0 0
1 2 7 5 2 5 5 0 0 4 2 5 0 0

• While multiplying by tens, put zero in ones column
• While multiplying by hundreds, put zero in ones and tens column.

Multiply: 5 6 7 8 2 3 4 3 2
× 2 4 1 × 1 2 4 × 3 6 5
3 6 4
× 2 1 5

3 6 4 5 8 0 4 6 3 5 6 9
× 2 1 5 × 2 1 4 × 2 5 4 × 3 1 4

148 Oasis School Mathematics Book-3

Multiplication in our Daily Life 2 4
× 2 5
Look and learn. 1 2 0
4 8 0
There are 24 hours in a day. How many hours are
there in 25 days? 6 0 0

\ There are 600 hours in 25 days.

There are 12 pencils in one dozen. How
many pencils are there in 56 dozens?

A man spends Rs 40 in a day. How much
does he spend in 15 days?

There are 24 biscuits in a packet. How many
biscuits are there in 20 such packets?

There are 35 oranges in a basket. How
many oranges are there in 18 baskets?

Oasis School Mathematics Book-3 149

A bus travels 48 km in an hour. How many
kilometres does it travel in 18 hours?

There are 224 boxes of apples, each of them
having 44 apples. How many apples are
there altogether?

A man spends Rs 415 in a day. How much
does he spend in 15 days?

An aeroplane flies 350 km in one hour. How
many kms does it cover in 24 hours?

A crate contains 24 bottles. How many
bottles are there in 255 crates?

In a school 525 students collected 16 stamps
each. How many stamps were collected in
all?

150 Oasis School Mathematics Book-3