Singapore Maths Method Latest Indonesian Syllabus 21st Century Learning Skills Textbook 100 RUPIAH 500 RUPIAH 100 RUPIAH 100 500 RUPIAH 500 20 000 RUPIAH Consulting author Dr Ngo Hea Choon
Singapore Maths Method Latest Indonesian Syllabus 21st Century Learning Skills Textbook First Published 2022 6001 Beach Road, #14-01 Golden Mile Tower, Singapore 199589. E-mail: [email protected] ISBN 978-981-17075-7-5 Consulting author Dr Ngo Hea Choon Distributed by PT. Penerbitan Pelangi Indonesia Ruko the Prominence, Block 38G No. 36, Jl. Jalur Sutera, Alam Sutera, Tangerang, 15143, Indonesia. Tel: [021]29779388 Fax: [021]30030507 Email: [email protected] Printed in Malaysia by The Commercial Press Sdn. Bhd. Lot 8, Jalan P10/10, Kawasan Perusahaan Bangi, Bandar Baru Bangi, 43650 Bangi, Selangor Darul Ehsan, Malaysia. 2022 All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, photocopying, mechanical, recording or otherwise, without the prior permission of
ii Preface MINDS-ON MATHS is an exciting new series that has been developed to match the latest Indonesian Mathematics syllabuses for Primary 1 to Primary 6. This series covers comprehensively all the basic competencies (Kompetensi Dasar) as prescribed by the Indonesian Ministry of Education. MINDS-ON MATHS is a complete mathematics programme that comprises the Textbook, Workbook, Teacher’s Guide and online resources. This series builds a strong foundation of the subject through the use of the well-researched and sound pedagogical principles. Adopting the Singapore Maths method, a world-class maths teaching approach, this series integrates the Indonesian curriculum and 21st century learning skills with the most effective methods of teaching. MINDS-ON MATHS is designed to meet the learning needs of primary-level pupils to understand and strengthen their mathematical concepts and problem-solving skills, as well as assisting teachers in preparing and conducting their Mathematics lessons. CPA approach Concepts and key skills within each chapter are developed in a structured and step-by-step manner following the popular Concrete Pictorial Abstract approach to help pupils gain a firm foundation in mathematics. The method uses a three-step learning model, which consistently introduces concepts in a systematic progression. It moves from the concrete to the visual representation and then to the abstract (questioning and solving written equations). Pupils are taught not only to know how to do something but also why it works. Indonesian Maths Syllabuses Singapore Maths Method 21st Century Learning Skills
iii The contents in this series are clearly structured and move up the levels to ensure a gradual build-up of skills as pupils progress from one stage to the next. At the same time, emphasis is placed on developing pupils’ 21st century skills, such as problem-solving and critical thinking skills. 21st Century Learning Skills Throughout the series, pupils are often challenged with problem-based questions in a fun and collaborative environment. This not only creates opportunities for pupils to think critically and reason logically, but also provides a platform for pupils to communicate effectively, work individually as well as in groups, and to use ICT tools in learning mathematics. 21st Century Learning Skills 5 3 2 3 + 2 = 5 Concrete Pictorial Abstract Critical Thinking Creativity Collaboration Communication MINDS-ON MATHS is designed to meet the individual needs of all learners. Pupils will find this textbook easy to use and understand. It will guide the pupils at a manageable pace to develop their love for maths and thus to inject confidence in them.
iv Contents Special features........................................................... VII Chapter 1 Numbers up to 1000 ............................................ 1 72 A Reading and writing numbers ................................... 2 B Place value and expanded form ............................... 5 C Comparing numbers ................................................. 7 D Ordering numbers..................................................... 9 E Number patterns ....................................................... 11 F Even numbers and odd numbers.............................. 16 Chapter 2a Addition and subtraction within 1000 .......... 21 A Addition without regrouping ...................................... 22 B Addition with regrouping ........................................... 25 C Subtraction without regrouping................................. 28 D Subtraction with regrouping...................................... 31 E Using addition and subtraction to solve word problems.......................................................... 34 Chapter 3s Using models (addition and subtraction) .. 392 A Simple word problems .............................................. 40 B Two-step word problems........................................... 49 Chapter 4 Multiplication ........................................................ 56 72 A Meaning of multiplication .......................................... 57 B Multiplication of 1-digit numbers............................... 60 C Solving word problems ............................................. 70 Kompetensi dasar 3.1 Menjelaskan makna bilangan cacah dan menentukan lambangnya berdasarkan nilai tempat dengan menggunakan model konkret serta cara membacanya 3.2 Membandingkan dua bilangan cacah 3.3 Menjelaskan dan melakukan penjumlahan dan pengurangan bilangan yang melibatkan bilangan cacah sampai dengan 999 dalam kehidupan sehari-hari serta mengaitkan penjumlahan dan pengurangan 4.1 Membaca dan menyajikan bilangan cacah dan lambangnya berdasarkan nilai tempat dengan menggunakan model konkkret 4.2 Mengurutkan bilanganbilangan dari bilangan terkecil ke bilangan terbesar atau sebaliknya 4.3 Menyelesaikan masalah penjumlahan dan pengurangan bilangan yang melibatkan bilangan cacah sampai dengan 999 dalam kehidupan sehari-hari serta mengaitkan penjumlahan dan pengurangan Kompetensi dasar 3.1 Menjelaskan perkalian dan pembagian yang melibatkan bilangan cacah dengan hasil kali sampai dengan 100 dalam kehidupan sehari-hari serta mengaitkan perkalian dan pembagian
v Chapter 5 Division ................................................................... 75 72 A Meaning of division................................................... 76 B Division as the opposite of multiplication.................. 81 C Dividing by 1-digit divisors........................................ 82 D Solving word problems involving division ................. 83 Chapter 6 Using models (multiplication and division) 872 A Word problems involving multiplication..................... 88 B Word problems involving division ............................. 92 Chapter 7a Money ........................................................................ 96 A Getting to know our money....................................... 97 B Exchanging money ................................................... 100 C Counting money........................................................ 104 D Comparing money .................................................... 106 Chapter 8s Length ...................................................................... 110 72 A Measuring length in metres and centimetres............ 111 B Comparing lengths.................................................... 115 C Solving word problems involving length.................... 119 Chapter 9 Mass ......................................................................... 127 72 A Measuring mass in kilograms and grams ................. 128 B Comparing masses................................................... 133 C Solving word problems involving mass..................... 136 Kompetensi dasar 3.5 Menjelaskan nilai dan kesetaraan pecahan mata uang 4.5 Mengurutkan nilai mata uang serta mendemonstarikan berbagai kesetaraan pecahan mata uang Kompetensi dasar 3.6 Menjelaskan dan menentukan panjang (termasuk jarak), berat, dan waktu dalam satuan baku, yang berkaitan dengan kehidupan sehari-hari 4.6 Melakukan pengukuran panjang (termasuk jarak), berat, dan waktu dalam satuan baku, yang berkaitan dengan kehidupan seharihari Kompetensi dasar 4.4 Menyelesaikan masalah perkalian dan pembagian yang melibatkan bilangan cacah dengan hasil kali sampai dengan 100 dalam kehidupan sehari-hari serta mengaitkan perkalian dan pembagian
vi Chapter 10 Time ........................................................................... 143 72 A Reading and writing time .......................................... 144 B Time taken in hours and minutes.............................. 150 C Months of the year.................................................... 152 Chapter 11 Fractions .................................................................. 157 A Understanding fractions............................................ 158 Chapter 12 Geometric shapes ................................................ 162 A Straight lines and curves .......................................... 163 B Two-dimensional (2-D) shapes ................................. 166 C Making pictures from shapes.................................... 168 D Drawing two-dimensional (2-D) shapes.................... 170 E Three-dimensional (3-D) shapes .............................. 173 Kompetensi dasar 3.8 Menjelaskan ruas garis dengan menggunakan model konkret bangun datar dan bangun ruang 3.9 Menjelaskan bangun datar dan bagun ruang berdasarkan ciri-cirinya 3.10 Menjelaskan pola barisan bangun datar dan bangun ruang menggunakan gambar atau benda konkret 4.8 Mengidentifikasi ruas garis dengan menggunakan model konkret bangun datar dan bangun ruang 4.9 Mengklasifikasi bangun datar dan bangun ruang berdasarkan ciri-cirinya 4.10 Memprediksi pola barisan bangun datar dan bangun ruang menggunakan gambar atau benda konkret Kompetensi dasar 3.7 Menjelaskan pecahan 1/2, 1/3, dan 1/4 menggunakan benda-benda konkret dalam kehidupan sehari-hari 4.7 Menyajikan pecahan 1/2, 1/3, dan 1/4 yang bersesuaian dengan bagian dari keseluruhan suatu benda konkret dalam kehidupan sehari-hari
vii Special features Chapter Opener Introduces concepts through thought-provoking questions to encourage critical thinking and develop analytical skill. Let’s Think ! Challenges pupils with non-routine questions that promote critical thinking and logical reasoning skills. Provides a list of suitable websites related to the chapter to aid pupils in revision and self-assessment. Maths Online States the learning objectives of the upcoming chapter. Learning Outcomes Directs pupils to the carefully selected videos online for further reinforcement and mastery of concepts. watch me Practice Provides exercises to reinforce pupils’ grasp of mathematical concepts. Contains different types of online activities and games that promote peer interaction and collaborative learning. maths battle Activity CORNER Provides practical activities to enhance pupils’ interest, knowledge and experience in learning Mathematics.
viii Special features Activity Provides an activity that engages in the application of knowledge of scientists, mathematicians and engineers. *Available in MINDS-ON MATHS Digital Handbook. Interesting and investigative real-life problems to challenge pupils in realistic and meaningful context. Mathematical Olympiad* quick quiz Provides numerous collections of printable online maths quizzes for pupils to boost their maths knowledge and improve speed with accuracy of maths skills. Helps pupils practise answering questions that promote higher order thinking skills (HOTS).
Chapter 1 Numbers up to 1000 What is the easiest way to count the building blocks? You should be able to • count, read and write up to 1000 using numbers and words • identify the place values of numbers up to 1000 • compare and order numbers up to 1000 • complete number patterns • know even numbers and odd numbers Learning Outcomes Maths Online http://bit.do/IPMT2-C1-MO-1 http://bit.do/IPMT2-C1-MO-2 http://bit.do/IPMT2-C1-MO-3 Maths Online Maths Online Maths Online 2 3
108 One hundred and eight 211 Two hundred and eleven 328 Three hundred and twenty-eight 469 Four hundred and sixty-nine 540 Five hundred and forty 647 Six hundred and forty-seven 769 Seven hundred and sixty-nine 818 Eight hundred and eighteen 952 Nine hundred and fifty-two 1000 One thousand 2 watch me Mathematics Grade 2 A Reading and writing numbers Read these numbers aloud.
3 CHAPTER 1 Numbers up to 1000 How many sticks are there? 100 200 300 400 401 402 403 14444244443 500 1442443 1442443 80 6 100 200 300 400 500 600 700 800 900 1000 There are 403 sticks. There are 586 sticks. There are 1000 sticks. 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 10 10 10 10 10 10 10 10
4 Mathematics Grade 2 Practice Count. Write in numerals and words. In numerals: In words: In numerals: In words: 100 100 100 100 10 10 In numerals: In words: 100 100 100 100 100 100 10 10 10 100 100 100 100 100 100 100 100 10 10 10 10 10 10
watch me CHAPTER 1 Numbers up to 1000 5 Hundreds Tens Ones 4 5 9 B Place value and expanded form The digit 4 in 459 is in the hundreds place. Its value is 400. The digit 5 in 459 is in the tens place. Its value is 50. The digit 9 in 459 is in the ones place. Its value is 9. 459 = 4 hundreds 5 tens 9 ones 459 = 400 + 5 + 9 In sentence form: 623 is 6 hundreds 2 tens and 3 ones. In expanded form: 623 = 600 + 20 + 3 In sentence form: 848 is 8 hundreds 4 tens and 8 ones. In expanded form: 848 = 800 + + 459 Hundreds Tens Ones 6 2 3 Hundreds Tens Ones 8 4 8
6 Mathematics Grade 2 Practice 1. Fill in the blanks. (a) 2. Write the place values and digit values of the underlined digits. 312 is 3 hundreds ten and ones. 312 = 300 + + 535 is hundreds tens and ones. 535 = + + Number Place value Digit value 98 150 258 Ones 689 600 976 (b) Hundreds Tens Ones 3 1 2 Hundreds Tens Ones 5 3 5
watch me CHAPTER 1 Numbers up to 1000 7 Hundreds Tens Ones 3 5 0 Hundreds Tens Ones 2 8 9 C Comparing numbers Which number is greater, 25 or 155? 25 is a two-digit number. 155 is a three-digit number. 155 has more digits than 25. Therefore, 155 is greater than 25. 155 > 25 Which number is smaller, 350 or 289? Compare the number of digits in each number. 25 155 Both numbers are three-digit numbers. Compare the hundreds. 2 hundreds is smaller than 3 hundreds. Therefore, 289 is smaller than 350. 289 < 350 350 289
8 Mathematics Grade 2 If both numbers have the same number of hundreds, compare the tens. If both numbers have the same numbers of hundreds and tens, we compare the ones. Practice Fill in the blanks with “>” or “<”. 1. 32 127 3. 425 804 5. 214 284 7. 785 769 2. 130 99 4. 251 152 6. 333 338 8. 926 629 Therefore, 369 is smaller than 385. 369 < 385 3 8 5 3 6 9 Compare the hundreds: They are the same. 3 8 5 3 6 9 Compare the tens: 6 tens is smaller than 8 tens. 385 369 Which number is smaller, 385 or 369? Conversely, 385 is greater than 369. 385 > 369
watch me CHAPTER 1 Numbers up to 1000 9 87 89 91 93 95 97 95 93 91 Ascending 89 Descending D Ordering numbers Arrange the following numbers in ascending order. 955 812 879 36 Compare the number of digits in each number. 36 has two digits. The rest of the numbers have three digits each. Therefore, 36 is the smallest number. Compare the hundreds. 9 hundreds is greater than 8 hundreds. Therefore, 955 is the greatest number. Compare the tens of 812 and 879. 1 ten is smaller than 7 tens. Therefore, 812 is smaller than 879. In ascending order: 36, 812, 879, 955 smallest greatest Ascending order means the order of numbers from the smallest to the greatest. Descending order means the order of numbers from the greatest to the smallest.
10 Mathematics Grade 2 Practice 1. Arrange these numbers in ascending order. (a) 587, 69, 530, 600 (b) 805, 369, 77, 850 2. Arrange these numbers in descending order. (a) 44, 189, 287, 155 (b) 428, 482, 650, 660 Arrange the following numbers in descending order. 365 689 698 680 All the numbers have three digits each. Compare the hundreds. 3 hundreds is smaller than 6 hundreds. Therefore, 365 is the smallest number. Compare the tens of 689, 698 and 680. 9 tens is greater than 8 tens. Therefore, 698 is the greatest among 689, 698 and 680. Compare the ones of 689 and 680. 9 ones is greater than 0 one. Therefore, 689 is greater than 680. In descending order: 698, 689, 680, 365 greatest smallest
watch me CHAPTER 1 Numbers up to 1000 11 E Number patterns What is the next number in this number pattern? 125 130 135 140 ? Each number is 5 more than the number before it. This number pattern is in increasing order. We can count on in steps of 5 to find the next number. What is the value of ♥ in this number pattern? 236 246 256 266 ♥ Each number is 10 more than the number before it. This number pattern is in increasing order. We can count on in steps of 10 to find the next number. 5 more than 140 is 145. Therefore, the next number is 145. 125 130 135 140 ? 5 more (+5) 5 more (+5) 5 more (+5) 5 more (+5)
12 Mathematics Grade 2 10 more than 266 is . Therefore, ♥ is . What is the value of ♦ in this number pattern? Using place value charts, 100 more than 447 is . Each number is 100 more than the number before it. This number pattern is in increasing order. 236 246 256 266 ♥ 10 more (+10) 10 more (+10) 10 more (+10) 10 more (+10) 147 247 347 447 ♦ 147 247 347 447 ♦ 100 more (+100) 100 more (+100) 100 more (+100) 100 more (+100) 4 4 7 5 4 7 100 more (+100)
13 CHAPTER 1 Numbers up to 1000 What is the next number in this number pattern? 356 354 352 350 ? Each number is 2 less than the number before it. This number pattern is in decreasing order. We can count back in steps of 2 to find the next number. 2 less than 350 is . Therefore, the next number is . What is the value of in this number pattern? 613 603 593 583 Each number is 10 less than the number before it. This number pattern is in decreasing order. We can count back in steps of 10 to find the next number. 356 354 352 350 ? 2 less (–2) 2 less (–2) 2 less (–2) 2 less (–2)
14 Mathematics Grade 2 10 less than 583 is . Therefore, is . What is the value of in this number pattern? Using place value charts, 100 less than 430 is . Each number is 100 less than the number before it. This number pattern is in decreasing order. 10 less (–10) 10 less (–10) 10 less (–10) 10 less (–10) 613 603 593 583 730 630 530 430 730 630 530 430 100 less (–100) 100 less (–100) 100 less (–100) 100 less (–100) 4 3 0 3 3 0 100 less (–100)
15 CHAPTER 1 Numbers up to 1000 Practice Fill in the missing numbers to complete the number patterns below. Then, describe the number patterns using “increasing” or “decreasing”. 1. 68, 73, 78, 83, 88, , 2. , 97, 107, , 127, 137, 147 3. 556, 554, , 550, , 546 , 544 4. 358, 348, 338, 328, 318, , 5. 258, 358, 458, 558, 658, , 6. , 668, 568, 468, 368, 268 Fill in the blanks. 1 1 1 1 1 1 3 3 2 1 1 4 6 4 1 1 5 13 5 1 Let’s Think !
16 watch me Mathematics Grade 2 F Even numbers and odd numbers Box A has 4 apples. We can pair them up evenly. Therefore, 4 is an even number. Box B has 3 apples. When we pair them up, one is left. Therefore, 3 is an odd number. Box A Box B 1 is an odd number. 3 is an odd number. 2 is an even number. 4 is an even number.
17 CHAPTER 1 Numbers up to 1000 5 is an odd number. 6 is an even number. 9 is an odd number. 10 is an even number. How do we know if a number greater than 10 is an odd number or an even number? 2, 4, 6, 8 and 10 are even numbers. 1, 3, 5, 7 and 9 are odd numbers. 7 is an odd number. 8 is an even number.
18 Mathematics Grade 2 Practice Identify the even numbers and odd numbers. 25 36 69 50 100 265 330 395 458 555 649 1000 Even numbers: Odd numbers: Form the greatest odd number with the three numbers above. 3 4 7 Numbers with 0, 2, 4, 6 and 8 in the ones place are even numbers. Numbers with 1, 3, 5, 7 and 9 in the ones place are odd numbers. 17 has 7 in the ones place. 7 is an odd number. Therefore, 17 is an odd number. Is 17 an odd number or an even number? 17 Let’s Think !
19 CHAPTER 1 Numbers up to 1000 ASK IMAGINE PLAN Button building There are many tall buildings in Jakarta and other cities. The person who designs and creates buildings is known as a building engineer. A telecommunication company hires you and your team to design and create a tall building by using buttons and clay. The building should stand on its own. The winner is the team with the tallest button building. All students can count until the building collapses. (Counting for 15 minutes means counting from 1 to 1000 approximately.) Suggested materials: buttons clay Tips: Think about the shape of the building. What are the common shapes of the buildings around you? Activity
20 Mathematics Grade 2 CREATE IMPROVE PRESENT
Chapter 2 Addition and subtraction within 1000 Can you solve the problem on the board? 532 + 17 = ? You should be able to • add and subtract numbers within 1000 without regrouping • add and subtract numbers within 1000 by regrouping ones, tens or hundreds Maths Online Maths Online Maths Online Maths Online Learning Outcomes Maths Online http://bit.do/IPMT2-C2-MO-2 http://bit.do/IPMT2-C2-MO-3 3 http://bit.do/IPMT2-C2-MO-4 4 http://bit.do/IPMT2-C2-MO-5 2 3 4
Mathematics 22 Grade 2 A Addition without regrouping 532 + 17 = Step 1: Write the numbers vertically. Make sure the hundreds, tens and ones places are lined up. Add the ones. Hundreds Tens Ones 5 3 2 1 7 9 + 2 ones + 7 ones = 9 ones Step 2: Add the tens. Hundreds Tens Ones 5 3 2 1 7 4 9 + 3 tens + 1 ten = 4 tens Step 3: Add the hundreds. Hundreds Tens Ones 5 3 2 1 7 5 4 9 + 5 hundreds + 0 hundred = 5 hundreds Therefore, 532 + 17 = 549. Hundreds Tens Ones Hundreds Tens Ones Hundreds Tens Ones watch me
CHAPTER 2 Addition and subtraction within 1000 23 683 + 204 = + Hundreds Tens Ones 6 8 3 2 0 4 7 Step 1: Add the ones. Hundreds Tens Ones 6 8 3 2 0 4 8 7 + Step 2: Add the tens. 3 ones + 4 ones = 7 ones 8 tens + 0 ten = 8 tens Hundreds Tens Ones Hundreds Tens Ones Hundreds Tens Ones 6 8 3 2 0 4 8 8 7 + Step 3: Add the hundreds. 6 hundreds + 2 hundreds = 8 hundreds Hundreds Tens Ones Therefore, 683 + 204 = 887.
Mathematics 24 Grade 2 Practice 1. Add. Use the place value chart to help you. (a) (b) 2. Add. (a) 208 + 41 = (b) 315 + 12 = (c) 421 + 133 = (d) 610 + 158 = (c) (d) (e) 88 + 201 = (f) 325 + 142 = H T O 5 1 5 + 6 4 H T O 3 3 0 + 3 2 4 H T O + H T O + H T O 2 1 6 + 1 7 0 H T O 5 6 3 + 2 2 5
CHAPTER 2 Addition and subtraction within 1000 25 B Addition with regrouping 327 + 38 = Step 1: Add the ones and regroup the ones. 7 ones + 8 ones = 15 ones Regroup the ones. 15 ones = 1 ten + 5 ones Step 2: Add the tens. 1 ten + 2 tens + 3 tens = 6 tens Step 3: Add the hundreds. 3 hundreds + 0 hundred = 3 hundreds Therefore, 327 + 38 = 365. Hundreds Tens Ones 1 3 2 7 3 8 5 + Hundreds Tens Ones 1 3 2 7 3 8 6 5 + Hundreds Tens Ones 1 3 2 7 3 8 3 6 5 + Hundreds Tens Ones 4 Hundreds Tens Ones 4 Hundreds Tens Ones 4 watch me
Mathematics 26 Grade 2 8 ones + 4 ones = 12 ones Regroup the ones. 12 ones = 1 ten + 2 ones 1 ten + 5 tens + 7 tens = 13 tens Regroup the tens. 13 tens = 1 hundred + 3 tens 1 hundred + 2 hundreds + 3 hundreds = 6 hundreds 258 + 374 = Therefore, 258 + 374 = 632. Hundreds Tens Ones 1 2 5 8 3 7 4 2 + Hundreds Tens Ones 1 1 2 5 8 3 7 4 3 2 + Hundreds Tens Ones 1 1 2 5 8 3 7 4 6 3 2 + Step 1: Add the ones and regroup the ones. Step 2: Add the tens and regroup the tens. Step 3: Add the hundreds. Hundreds Tens Ones 4 Hundreds Tens Ones 4 Hundreds Tens Ones
CHAPTER 2 Addition and subtraction within 1000 27 Practice 1. Add. Use the place value chart to help you. (a) (b) 2. Add. (a) 326 + 37 = (b) 409 + 73 = (c) 274 + 277 = (d) 169 + 758 = (c) (d) (e) 473 + 166 = (f) 658 + 254 = H T O 1 5 8 + 1 7 H T O 3 4 8 + 2 3 9 H T O + H T O + H T O 2 2 5 + 9 6 H T O 1 7 4 + 4 5 0
Mathematics 28 Grade 2 C Subtraction without regrouping 648 – 25 = Step 1: Write the numbers vertically. Make sure the hundreds, tens and ones places are lined up. Subtract the ones. Hundreds Tens Ones 6 4 8 2 5 3 – 8 ones – 5 ones = 3 ones Step 2: Subtract the tens. Hundreds Tens Ones 6 4 8 2 5 2 3 – 4 tens – 2 tens = 2 tens Step 3: Subtract the hundreds. Hundreds Tens Ones 6 4 8 2 5 6 2 3 – 6 hundreds – 0 hundred = 6 hundreds Therefore, 648 – 25 = 623. Hundreds Tens Ones Hundreds Tens Ones Hundreds Tens Ones watch me
CHAPTER 2 Addition and subtraction within 1000 29 4 ones – 4 ones = 0 one 8 tens – 5 tens = 3 tens 7 hundreds – 2 hundreds = 5 hundreds Therefore, 784 – 254 = 530. 784 – 254 = Step 1: Subtract the ones. Hundreds Tens Ones 7 8 4 2 5 4 0 – Step 2: Subtract the tens. Hundreds Tens Ones 7 8 4 2 5 4 3 0 – Step 3: Subtract the hundreds. Hundreds Tens Ones 7 8 4 2 5 4 5 3 0 – Hundreds Tens Ones 4 Hundreds Tens Ones 4 Hundreds Tens Ones 4
Mathematics 30 Grade 2 Practice 1. Subtract. Use the place value chart to help you. (a) (b) 2. Subtract. (a) 258 – 27 = (b) 473 – 13 = (c) 586 – 215 = (d) 660 – 340 = (c) (d) (e) 768 – 535 = (f) 923 – 410 = H T O 3 6 4 – 1 2 H T O 3 3 3 – 1 2 1 H T O – H T O – H T O 2 7 6 – 5 0 H T O 6 7 8 – 2 5 1
CHAPTER 2 Addition and subtraction within 1000 31 D Subtraction with regrouping 452 – 25 = Step 1: Regroup the ones and subtract the ones. 5 tens = 4 tens 10 ones Regroup 1 ten into 10 ones. 10 ones + 2 ones = 12 ones 12 ones – 5 ones = 7 ones Step 2: Subtract the tens. 4 tens – 2 tens = 2 tens Step 3: Subtract the hundreds. Hundreds Tens Ones 4 12 4 5 2 2 5 7 – Hundreds Tens Ones 4 12 4 5 2 2 5 2 7 – Hundreds Tens Ones 4 12 4 5 2 2 5 4 2 7 – 4 hundreds – 0 hundred = 4 hundreds Therefore, 452 – 25 = 427. Hundreds Tens Ones Hundreds Tens Ones Hundreds Tens Ones watch me
Mathematics 32 Grade 2 7 hundreds = 6 hundreds 10 tens Regroup 1 hundred into 10 tens. 10 tens + 4 tens = 14 tens 14 tens – 8 tens = 6 tens 6 ones – 5 ones = 1 one 6 hundreds – 5 hundreds = 1 hundred 746 – 585 = Therefore, 746 – 585 = 161. Step 1: Subtract the ones. Hundreds Tens Ones 7 4 6 5 8 5 1 – Step 2: Regroup the hundreds and tens. Step 3: Subtract the hundreds. Hundreds Tens Ones 6 14 7 4 6 5 8 5 1 6 1 – Hundreds Tens Ones 6 14 7 4 6 5 8 5 6 1 – Hundreds Tens Ones Hundreds Tens Ones Hundreds Tens Ones
CHAPTER 2 Addition and subtraction within 1000 33 Practice 1. Subtract. Use the place value chart to help you. (a) (b) 2. Subtract. (a) 137 – 38 = (b) 246 – 19 = (c) 410 – 153 = (d) 663 – 591 = (c) (d) (e) 654 – 206 = (f) 863 – 471 = H T O 1 2 1 – 3 8 H T O 4 2 6 – 1 4 1 H T O – H T O – H T O 2 3 0 – 2 7 H T O 6 1 7 – 3 2 8
Mathematics 34 Grade 2 A Mathematics book has 260 pages. A Science book has 180 pages. How many more pages does the Mathematics book have than the Science book? 260 – 180 = The Mathematics book has 80 pages more than the Science book. E Using addition and subtraction to solve word problems There are 325 chicks and 158 ducklings on a farm. How many animals are there on the farm? 325 + 158 = There are 483 animals on the farm. There are 3 1 2 5 chicks. There are + 1 5 8 ducklings. In total, there are 4 8 3 animals. 1 16 The Mathematics book has 260 pages. The Science book has – 180 pages. The Mathematics book has 80 pages more.
CHAPTER 2 Addition and subtraction within 1000 35 Solve the following word problems. Practice 1. Philip has 257 marbles. He gives 195 marbles to his brother. How many marbles does he have now? 257 – 195 = Philip has 257 marbles. He gives – 195 marbles to his brother. He has marbles now. Philip has marbles now. 2. Harry reads 173 pages of a storybook. There are 95 pages to go. What is the total number of pages in the storybook? 173 + 95 = Harry reads 173 pages. There are + 95 pages to go. There are pages in the storybook. There is a total of pages in the storybook. Always check your answers.
Mathematics 36 Grade 2 3. Mary has 358 stamps. In a week, she manages to collect another 163 stamps. How many stamps does she have altogether? 4. Alice has 136 beads. She has 59 more beads than Shelly. How many beads does Shelly have?
CHAPTER 2 Addition and subtraction within 1000 37 ASK IMAGINE PLAN Paper stands up Look at the objects around you. They have many shapes. A can is a cylinder while a box is a cuboid. A book can stand on its own in many positions. You are required to design and create a structure made of paper. Your structure should be as tall as possible with fewer pieces of paper. It should be able to stand on its own for at least 10 minutes. Suggested material: A4 paper Tips: 1. Look at the legs of your desk. Are the legs cylinders or cuboids? 2. The best structure depends on its height and cost. Activity
Mathematics 38 Grade 2 CREATE IMPROVE PRESENT
Chapter 3 Using models (addition and subtraction) You should be able to • draw models involving addition and subtraction • solve two-step word problems involving addition and subtraction • solve two-part word problems involving addition and subtraction We can use bar models to represent numbers. Learning Outcomes Maths Online http://bit.do/IPMT2-C3-MO-1 http://bit.do/IPMT2-C3-MO-2 http://bit.do/IPMT2-C3-MO-3 Maths Online Maths Online Maths Online 2 3
40 Mathematics Grade 2 A Simple word problems 4 + 5 = 9 Kenny has 9 toys altogether. Kenny has 4 toy robots and 5 toy cars. How many toys does Kenny have altogether? We can use models to show the number of Kenny’s toys. Bar models Number of toy robots Number of toy robots ? Number of toy cars Number of toy cars + 4 5 Total number of toys watch me
CHAPTER 3 Using models (addition and subtraction) 41 There are flowers in the garden altogether. Joey has 57 stickers. Her brother gives her 35 stickers. How many stickers does Joey have now? There are 44 roses in the garden. There are 28 daisies in the garden. How many flowers are there in the garden altogether? Joey has stickers now. 57 + 35 = = Adding sets of obejcts Number of stickers Joey has now ? Number of stickers Joey has at first 57 35 Number of stickers Joey receives ? Number of roses Number of daisies 44 28