Ready, Set, Go! Play this game! Carry out this activity · Dr Fong Ho Kheong • Chelvi Ramakrishnan • Gan Kee Soon Singapore Methodology with 100% alignment to the Indonesian syllabus

Dr Fong Ho Kheong • Chelvi Ramakrishnan • Gan Kee Soon

Singapore Methodology with 100% alignment to the Indonesian

syllabus (Kurikulum 2013)

New Maths Champion is an updated edition of the successful Singapore primary maths series Maths Champion, with 100% alignment to the latest Indonesian syllabus (Kurikulum 2013). Drawing from extensive research and feedback from educators and students, this series strengthens mathematical conceptual understanding to meet the needs of educators and students.

Ready, Set, Go! introduces concepts in a format that is engaging and easy to understand, with questions that allow for immediate assessment of students’ understanding.

Carry out this activity and Play this game! develop and reinforce skills, concepts and problem-solving strategies through cooperative learning.

The direct correlation of the Workbook to the Textbook allows for thorough practice and assessment. Revisions consolidate learning and promote long-term retention of what has been learnt.

New Maths Champion comprises• Textbook•Workbook• Teacher’s Guide

© 2011 Marshall Cavendish International (Singapore) Private Limited

© 2014 Marshall Cavendish Education Pte Ltd.

This English edition is licensed to Mentari Books.

Exclusively distributed in Indonesia by:

MENTARI BOOKS

Rukan Sentra Niaga Puri Indah

Block T1 – 14, Puri Indah

West Jakarta 11610

Tel: (021) 5890 1900

: 0855 888 1948

Fax: (021) 5890 0818

E-mail: [email protected]

Website: www.mentarigroups.com

First published 2012

Second edition 2018

First reprinted 2019

All rights reserved.

© 2018, Marshall Cavendish Education Pte Ltd. This English edition licensed to

Mentari Books. All rights reserved. No part of this publication may be reproduced or

transmitted in any form or by any means, or stored in any retrieval system of any

nature without the prior written permission of Marshall Cavendish Education Pte Ltd.

New Maths Champion Textbook 4

Aligned with Indonesian syllabus (Kurikulum 2013)

Preface

is specially designed to meet the requirements of Kurikulum 2013 for Primary 1 to

Primary 6 in Indonesia. The topic coverage in each level is arranged to address all the basic

competencies (Kompetensi Dasar) of the level prescribed in the syllabus. This series uses

the Singapore approach to teaching mathematics, which is internationally recognised as

one of the best in the world.

uses Concrete-Pictorial-Abstract (CPA) approach, which is proven to be a

very effective method. The content development of each topic matches the child’s

developmental age and is carefully designed in spiral progression. Extra contents

with (*) are added to maintain this spiral progression.

gives special emphasis on the development of conceptual understanding

and creative/critical thinking skills to build a firm foundation in mathematics. After the

introduction of new concepts, students are invited to apply what they have learnt through

hands-on activities and collaborative games. The textbook offers a number of engaging

and fun activities that will stimulate students’ interest in the topic and consolidate their

knowledge and understanding.

commits to nurture young Indonesians to be efficient problem solvers who are

competent to face the changing world in the future.

Be a maths champion!

Write an improper fraction for the shaded parts.

There are 5 thirds in 123 .

123 =

13

+ 13 +

13

+ 13

+ 13

= 53

Write an improper fraction for the shaded parts.

There are quarters in 114 .

114 = + + + +

=

There are fifths in 225 .

225 =

a

b

3

2

33

, 43

, 53

and 63

are equal to or greater than 1.

They are called improper fractions.

Mr Harry has some strips of wire.

Look at Strip D. It is 113 m long.

There are 4 thirds in 113 .

113 =

13

+ 13 +

13 +

13

= 43

A

B

C

D

33 m or 1 m

13

43 m or 1 m

23m

13m

= 1 third

= 2 thirds

= 3 thirds

= 4 thirds

13

23

33

43

improper fractions

0 2

0

1

13

23

43

53

131 2

31

33

63

Ready, Set, Go!

1= 33

= 13

+ 13 +

13

Improper FractionsLesson 2

1

9392 Fractions (2) Fractions (2)Chapter 5 Chapter 5

New important mathematicalterms are emphasised.

Questions allow forimmediate assessment ofconcepts or skills learnt.

Engaging and highly scaffoldedReady, Set, Go! introduces concepts,

skills or problem solving strategies.

Using This Book

has some special features. Find out what they are for and use them to help you

learn as you use this book.

Questions allow forimmediate assessment ofconcepts or skills learnt.

The big square is divided into 100 equal parts. 25 parts are shaded.

So, 25 out of 100 parts are shaded.

25100 of the big square is shaded.

25% of the big square is shaded.

% of the big square is shaded.

% of the big square is not shaded.

Express each of the following as a percentage.

72 out of 100 is %.

39 out of 100 is %.

4

a

b

What percentage of the whole is shaded?What percentage of the whole is not shaded?

2

3

149PercentageChapter 7

Area of a triangle = 12 x base x height

In triangle PQR, QR is the base and PS is the height.

1step

Copy Figure 1 on a piece of square grid paper.

2step

Then, cut out triangles PVX and VRX.

3step

Rearrange the two triangles as shown in Figure 2.

Figure 1 Figure 2

Area of triangle PQR = area of rectangle

= 12

× area of rectangle

= 12

× QR × TR

= 12

× QR ×

= 12

× base ×

1 cm

1 cm

U T P

Q R S

VX

U T P

Q R S

V XW

Carry out this activity.

5

243Area And PerimeterChapter 12

136 DecimalsChapter 6

The players take turns to think of a decimal between 0 and 1.

Players play 2 rounds each. At each round, the players discuss

their answers.

Work in groups of three.

Thefirstplayerthinksofadecimalbetween

0 and 1. He tells the other players the decimal.

The second player says a decimal between 0 and

1thatisgreaterthanthefirstplayer’sdecimal.

The third player says a decimal between 0 and 1

thatissmallerthanthefirstplayer’sdecimal.

Returnthecardstothedeckandshuffleit.

Players take turns to play.

After playing 3 rounds each, the player with

the most number of correct answers wins.

Make a set of cards using these decimals:

Shufflethecards.

Thefirstplayerdraws3 cards. He arranges the decimals in order,

beginning with the smallest.

The other player checks his answer.

12

Play this game!

a

0.5 0.05 0.6 0.07

0.17 1.7 0.71 0.16

1.5 1.06 1.61 0.76

1step

2step

3step

4step

I can choose any decimal between 0 and 1 except 0.001 and 0.999.

Players: 2

You need: • 12 cards

b

1step

2step

3step

WB 4, p 105Practice 4B

Opportunities to enjoy maths and collaborate with friends through Play this game!

Carry out this activity offers hands-on and active learning that involves the use of

mathematics.

Thinking questions to stimulate creative and critical thinking skills during the interactive teaching-learning process.

Kompetensi Dasar

Kompetensi Dasar

3.3 Menjelaskan dan melakukan penaksiran dari jumlah, selisih, hasil kali, dan hasil bagi dua bilangan cacah maupun pecahan dan desimal

4.3 Menyelesaikan masalah penaksiran dari jumlah, selisih, hasil kali, dan hasil bagi dua bilangan cacah maupun pecahan dan desimal

3.4 Menjelaskan faktor dan kelipatan suatu bilangan

3.5 Menjelaskan bilangan prima

3.6 Menjelaskan dan menentukan faktor persekutuan, faktor persekutuan terbesar (FPB), kelipatan persekutuan, dan kelipatan persekutuan terkecil (KPK) dari dua bilangan berkaitan dengan kehidupan sehari-hari

4.4 Mengidentifikasi faktor dan kelipatan suatu bilangan

4.5 Mengidentifikasi bilangan prima

4.6 Menyelesaikan masalah yang berkaitan dengan faktor persekutuan, faktor persekutuan terbesar (FPB), kelipatan persekutuan, dan kelipatan persekutuan terkecil (KPK) dari dua bilangan berkaitan dengan kehidupan sehari-hari

Whole Numbers (1)

Factors And Multiples

Whole Numbers (2)

Lesson 1 Factors 56 Lesson 2 Multiples 59 Lesson 3 Prime Numbers 62 Lesson 4 Finding The Highest Common Factor (HCF)

By Prime Factorisation 67 Lesson 5 Finding The Lowest Common Multiple (LCM)

By Prime Factorisation 69

Lesson 1 Multiplication By A 1-Digit Number 34 Lesson 2 Multiplication By A 2-Digit Number 39 Lesson 3 Division By A 1-Digit Number 45 Lesson 4 Word Problems 50

Lesson 1 Numbers To 100 000* 10 Lesson 2 Place Value* 13 Lesson 3 Comparing Numbers Within 100 000* 17 Lesson 4 Rounding Off Numbers To The Nearest Ten 21 Lesson 5 Rounding Off Numbers To The Nearest

Hundred 26 Lesson 6 Estimation 30

Contents1Chapt rChapterChapter

3Chapt rChapterChapter


Fractions (1)

Fractions (2)

Lesson 1 Numerator And Denominator 72 Lesson 2 Understanding Equivalent Fractions 73 Lesson 3 More Equivalent Fractions: Short Cut 76 Lesson 4 Comparing And Ordering Fractions 79

Lesson 1 Mixed Numbers 87 Lesson 2 Improper Fractions 92 Lesson 3 Conversion Of Fractions 96 Lesson 4 Fractions Of A Set 100 Lesson 5 Word Problems 104 Lesson 6 Rounding Off And Estimation Of Fractions 108



3.1 Menjelaskan pecahan-pecahan senilai dengan gambar dan model konkret

4.1 Mengidentifikasi pecahan-pecahan senilai dengan gambar dan model konkret

3.2 Menjelaskan berbagai bentuk pecahan (biasa, campuran, desimal, dan persen) dan hubungan di antaranya

3.3 Menjelaskan dan melakukan penaksiran dari jumlah, selisih, hasil kali, dan hasil bagi dua bilangan cacah maupun pecahan dan desimal

3.7 Menjelaskan dan melakukan pembulatan hasil pengukuran panjang dan berat ke satuan terdekat

4.2 Mengidentifikasi berbagai bentuk pecahan (biasa, campuran, desimal, dan persen) dan hubungan di antaranya

4.3 Menyelesaikan masalah penaksiran dari jumlah, selisih, hasil kali, dan hasil bagi dua bilangan cacah maupun pecahan dan desimal

4.7 Menyelesaikan masalah pembulatan hasil pengukuran panjang dan berat ke satuan terdekat

Decimals

Percentage

Lesson 1 Understanding Tenths 112 Lesson 2 Understanding Hundredths 118 Lesson 3 Understanding Thousandths 125 Lesson 4 Comparing Decimals 132 Lesson 5 Fractions And Decimals 137 Lesson 6 Rounding Off Decimals 142 Lesson 7 Rounding Off The Measurement Of Length

And Mass 147 Lesson 8 Estimation Of Decimals 149

Lesson 1 Per Cent 151



Kompetensi Dasar

Kompetensi Dasar

Angles

Lines And Angles

Lesson 1 Naming Angles 156 Lesson 2 Measuring Angles 157 Lesson 3 Drawing Angles To 1800 160 Lesson 4 8-point Compass* 162

Lesson 1 Perpendicular Lines 167 Lesson 2 Parallel Lines 172 Lesson 3 Angles On A Straight Line 177 Lesson 4 Angles At A Point 181 Lesson 5 Vertically Opposite Angles 185



3.12 Menjelaskan dan menentukan ukuran sudut pada bangun datar dalam satuan baku dengan menggunakan busur derajat

4.12 Mengukur sudut pada bangun datar dalam satuan baku dengan menggunakan busur derajat

Kompetensi Dasar

Kompetensi Dasar

Polygons Lesson 1 Polygons 190 Lesson 2 Angles Of A Triangle* 193 Lesson 3 Properties Of Quadrilaterals* 200

10Chapt rChapterChapter3.8 Menganalisis sifat-sifat segibanyak beraturan dan segibanyak tidak beraturan

4.8 Mengidentifikasi segibanyak beraturan dan segibanyak tidak beraturan

Kompetensi Dasar

3.10 Menjelaskan hubungan antar garis (sejajar, berpotongan, berhimpit) menggunakan model konkret

4.10 Mengidentifikasi hubungan antar garis (sejajar, berpotongan, berhimpit) menggunakan model konkret

145° 145°

100 110 120130

140150

160170

180

8070

60

50

40

3020

100 0

1020

30

40

50

6070

80100110

120

130

140

150

160

170

180

90100 110 120

130

140150

160170

180

8070

60

50

40

3020

100 0

1020

30

40

50

6070

80100110

120

130

140

150

160

170

180

90

A

B C

Kompetensi Dasar

Kompetensi Dasar

Bar Graphs Lesson 1 Making Bar Graphs With Scales 250 Lesson 2 Reading And Interpreting Bar Graphs 256



3.11 Menjelaskan data diri peserta didik dan lingkungannya yang disajikan dalam bentuk diagram batang

4.11 Mengumpulkan data diri peserta didik dan lingkungannya dan menyajikan dalam bentuk diagram batang

Area And Perimeter

Lesson 1 Square Centimetres (cm2) 210 Lesson 2 Square Metres (m2) 212 Lesson 3 Area Of A Rectangle And A Square 215 Lesson 4 Perimeter And Area 221 Lesson 5 More Area Of A Rectangle And A Square 223 Lesson 6 More Perimeter Of A Rectangle And A Square 227 Lesson 7 Base And Height Of A Triangle 230 Lesson 8 Finding The Area Of A Triangle 233 Lesson 9 Composite Figures 239 Lesson 10 Word Problems 246

3.9 Menjelaskan dan menentukan keliling dan luas persegi, persegipanjang, dan segitiga serta hubungan pangkat dua dengan akar pangkat dua

4.9 Menyelesaikan masalah berkaitan dengan keliling dan luas persegi, persegipanjang, dan segitiga termasuk melibatkan pangkat dua dengan akar pangkat dua

Glossary 260

1

10 Whole Numbers (1)Chapter 1

Whole Numbers (1)

Lesson 1

1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000,

10 thousands = 1 ten thousand

OnesTensTen

Thousands Thousands Hundreds

10 000

Let’s read the numbers. What number comes next?

10 000ten thousand

OnesTensTen


9000

1

Ready, Set, Go!

Lesson 1 Numbers To 100 000*

* Extra content to maintain spiral progression in the development of all related mathematical concepts, skills and knowledge.

11Whole Numbers (1)Chapter 1

Let’s read and show the numbers 15 000 and 73 486 in place value charts.

15 000fifteen thousand

OnesTensTen


1 5 0 0 0

73 486seventy-three thousand, four hundred and eighty-six

OnesTensTen


7 3 4 8 6

12 059twelve thousand and fifty-nine

What are the missing headings?

1 2 0 5 9

2

a

b

3


What is the number in words?

OnesTensTen


5 6 8 1 7

What is the number in numerals?

OnesTensTen


ten thousand, two hundred and seventy-three

Let’s read the number pattern. What number comes next?

10 000, 20 000, 30 000, 40 000, 50 000, 60 000, 70 000, 80 000, 90 000,

10 ten thousands = 1 hundred thousand

100 000 one hundred thousand

What comes immediately after 99 999?

4

5

6

What is the number in words?

47 048 90 015 86 300 70 005

7

a b c d

WB 4, p 9Practice 1

You are given these play money:

Five Rp 10.000,00 Ten Rp 1.000,00 Five Rp 100,00

Use the notes given to show the amount of money.

Your friend will check you answer.Rp 24.100,00 Rp 59.400,00 Rp 37.500,00


8

a b c


Place Value*

Let’s look at the number 31 798.

OnesTensTen


3 1 7 9 8

thirty-one thousand, seven hundred and ninety-eight

In 31 798:

the digit 3 is in the ten thousands place

the digit 3 stands for 30 thousands or 30 000the value of the digit 3 is 30 000

the digit 1 is in the thousands place

the digit 1 stands for 1 thousand or 1000the value of the digit 1 is 1000

the digit 7 is in the hundreds place

the digit 7 stands for 7 hundreds or 700the value of the digit 7 is 700

the digit 9 is in the tens place

the digit 9 stands for 9 tens or 90the value of the digit 9 is 90

the digit 8 is in the ones place

the digit 8 stands for 8 ones or 8the value of the digit 8 is 8.

Lesson 2

1



Let’s look at the number 53 827.

OnesTensTen


5 3 8 2 7

In 53 827:

the digit 5 is in the place

the digit 5 stands for

the value of the digit 5 is

the digit 3 is in the place

the digit 3 stands for

the value of the digit 3 is .

Find the missing numbers.

In 42 653, the digit is in the ten thousands place.

In 63 971, the digit 9 is in the place.

In 20 974, the digit in the thousands place is .

In 56 301, the value of the digit 3 is .

In 70 569, the digit 7 stands for .

In 81 465, the digit 1 stands for .

a

b

c

d

e

f

3

2

What does the digit 6 stand for in each of the following 5-digit numbers?

63 814 96 781 20 563

4

a b c


31 798 = 30 000 + 1000 + 700 + 90 + 8

= 31 000 + 798


6424 = thousands + 4 hundreds + 2 tens + 4 ones

50 328 = + 300 + 20 + 8

3 0 0 0 0

1 0 0 0

7 0 0

9 0

8

3 1 7 9 8

thirty-one thousand, seven hundred and ninety-eight

a

b

What does the digit 5 stand for in each number?

27 058 85 027 52 708

In 69 417, what is the value of each digit?


18 294 = 1 ten thousand + thousands + 2 hundreds + 9 tens + 4 ones

47 093 = + 7000 + 90 + 3

5

6

7

9

8

a

a

b

b c


Work in groups of four.

Your teacher will give each group 10 counters and a place value chart.

The group places the counters in the place value chart to form a

5-digit number. Pupils may choose not to use all the counters given.

OnesTensTen


The first player writes the value of each digit in the 5-digit number

formed like this:

The group checks the answer. The first player gets 1 point if his answer is

correct.

The group rearranges the counters on the place value chart to form another

5-digit number.

Players take turns to write the values of the digits in the numbers formed.

Each player plays 3 rounds.

WB 4, p 11Practice 2


The player with the highest score wins!

10

1step

2step

3step

4step

5step

6step


OnesTensTen


9 3 0 8 5

7 6 1 0 5

OnesTensTen


3 6 5 2 0

3 7 8 5 9

Which number is greater, 93 085 or 76 105?

Compare the ten thousands between the two numbers.

9 ten thousands is greater than 7 ten thousands.

So, 93 085 is greater than 76 105.

Which number is smaller, 36 520 or 37 859?

First, compare the ten thousands between the two numbers.

They are the same.

Then, compare the thousands between the two numbers.

6 thousands is smaller than 7 thousands.

So, 36 520 is smaller than 37 859.

Comparing Numbers Within 100 000*

We can compare numbers by using the place value charts to help us.

Lesson 3

1

2

Which is greater?

90 847 or 69 948 64 515 or 65 500

31 256 or 31 265 19 283 or 19 289

3

a

c

b

d



OnesTensTen


6 2 3 5 7

9 6 3 8

2 8 9 8 6

Which is smaller?

42 100 or 41 002 16 935 or 16 918

Arrange the numbers 62 357, 9638 and 28 986 in order.

Begin with the greatest.

Compare the ten thousands among the numbers.

So, the numbers arranged in order beginning with the greatest are:

62 357, 28 986, 9638

Arrange the following numbers in order. Begin with the smallest.

9456, 73 842, 30 512

41 325, 31 425, 51 324, 14 325

27 084, 20 784, 27 840, 20 874

2 ten thousands is greater than 0 ten thousands.

6 ten thousands is greater than 0 ten thousands and

2 ten thousands.

greatest

4

5

a b

6

a

b

c


Look at these two numbers: 65 123 and 67 123.

Compare the thousands between the two numbers.

65 123 is 2000 less than 67 123.

2000 more than 65 123 is .

67 123 is 2000 more than 65 123.

2000 less than 67 123 is .

Look at these two numbers: 37 625 and 7625.

30 000 more than 7625 is .

is 30 000 less than 37 625.


30 000 less than 34 200 is .

is 20 000 more than 53.

100 more than 58 967 is .

Find the rule for each number pattern. Then complete the number pattern.

37 642, 57 642, , 97 642

8500, , 18 500, 23 500

2985, 2885, , 2685, , 2485

24 701, 26 702, 28 703, ,

18 079, 20 079, 20 279, 22 279, 22 479, , , 26 679

OnesTensTen


3 7 6 2 5

7 6 2 5

OnesTensTen


6 5 1 2 3

6 7 1 2 3

7

8

9

10

a

a

a

b

b

b

d

c

c

e


Work in groups of four.

Make four sets of number cards from 1 to 9.

Shuffle the number cards.

Take turns to draw five number cards each.

Arrange your number cards to form a 5-digit number.

Compare your 5-digit number with those formed by the other

members in your group. Then arrange the numbers in order,

beginning with the greatest.


11


1step

2step

3step

4step

5step


Ribbon A is 82 cm long.

82 is between 80 and 90.

It is nearer to 80 than to 90.

82 is 80 when rounded off to the nearest ten.

We say 82 is approximately equal to 80.

We write 82 ≈ 80.

So, Ribbon A is 80 cm long when rounded off to

the nearest ten centimetres.

85 90

82

80

Ribbon A

Rounding Off Numbers To The Nearest Ten

Ready, Set, Go!

We use the approximation sign ≈

to stand for approximately equal to. It shows rounding off

of the numbers.

Lesson 4

1


Ribbon B is 17 cm long.



17 is when rounded off to the nearest ten.

17 ≈

Ribbon B is cm long when rounded off to the nearest ten centimetres.

Ribbon C is 95 cm long.

95 is exactly halfway between 90 and 100.


95 ≈ 100Ribbon C is 100 cm long when rounded off to the nearest ten centimetres.

Ribbon C

Ribbon B

17

10 15 20

95

10090 95

2

3


On a sheet of paper, copy the number line as shown below.

Mark each number with a cross ( ) on the number line.

Then round the number off to the nearest ten and circle it.

29 36 45 14

Round off each number to the nearest ten.

42 97 25 64

Round off 863 to the nearest ten.



863 is when rounded off

to the nearest ten.

863 ≈




4156 is when rounded off

to the nearest ten.

4156 ≈


20

13

10 30 40 50

Example13

865 870860

863

4156

4155 41604150

4

5

6

7

a

a

b

b

c d

dc




6455 is when rounded off to the nearest ten.

6455 ≈

For each number, draw a number line.

Then mark the number with a cross ( ) on the number line.

Lastly, round off the number to the nearest ten and circle it.

64556450 6460

Look at each number and find the nearest ten before and after it.

Here, the number 306 lies between these two nearest tens.

So, the number line for 306 should start at 300 and end at 310.

615 4381 9098

300 306 310nearest ten before it nearest ten after it


Example306

305300

306

310

8

9

a b c

For each number, where do I start and end the number line?


Work in pairs.

Use number lines to help you.

Find all the numbers that give the following answers when rounded off to

the nearest ten.

(i) 50 (ii) 570 (iii) 5000

For each set of answers in a , which is

(i) the smallest number (ii) the greatest number

Find

the smallest number the greatest number

that gives 5470 when rounded off the nearest ten.

10

11

a

b

a b


Example60

55

55 6050 65 70

56 57 58 59 61 62 63 64

55, 56, 57, 58, 59, 61, 62, 63 and 64 give the answer 60 when rounded

off to the nearest ten.

(i) 55 is the smallest number (ii) 64 is the greatest numberb

a

54705460 5480



The volume of water in Container A is 223 ml.



So, 223 is 200 when rounded off to the nearest hundred.

223 ≈ 200

The volume of water in Container A is 200 ml when rounded off to the

nearest hundred millilitres.

The volume of water in Container B is 287 ml.

287 is between and 300.It is nearer to 300 than to 200.So, 287 is 300 when rounded off to the nearest hundred.

287 ≈ 300

The volume of water in Container B is 300 ml when rounded off to the


Rounding Off Numbers To The Nearest Hundred

Container A

Container B

223

250 300200

287

250 300200

Ready, Set, Go!

Lesson 5

1

2


The volume of water in Container C is 650 ml.



650 ≈ 700

The volume of water in Container C is 700 ml when rounded off to the


Round off each of the following to the nearest hundred.

216 502 340 985

125 cm 872 kg 359 m 997 ø

Round off 2372 to the nearest hundred.




2372 ≈ 2400

Container C

600 650 700

2300 2350 2400

2372

3

4

5

a b c d

e f g h


Round off 9632 to the nearest hundred.

9632 is between and .

9632 is nearer to than to .

9632 is when rounded off to the nearest hundred.

9632 ≈

For each number, draw a number line.

Then mark the number with a cross ( ) on the number line.

Lastly, round off the number to the nearest hundred and circle it.

Look at each number and find the nearest hundred before and after it.

Here, the number 8950 lies between these two nearest hundreds.

So, the number line for 8950 should start at 8900 and end at 9000.

516 940 5026

4158 7902 8048

8950 is 9000 when rounded off to the nearest hundred.

Example

8950

970096509600

900089508900

8900nearest hundred before it nearest hundred after it

8950 9000

6

7

a b c

d e f


Find all the numbers that give 2800 when rounded off to the nearest

hundred. Mark these numbers with a cross ( ) on the number line.

Which of these is the smallest number?

Which of these is the greatest number?

Find

the smallest number

the greatest number

that gives 9300 when rounded off to the nearest hundred.

9200 9300 9400

2700 2800 2900

A number when rounded off to the nearest hundred is 2800.

Round off each number to the nearest ten and hundred.

9

8

10

a

b

c

ab


NumberRounded off to the nearest

ten hundred

68

482

3209

7735

a

b

c

d


Estimation

Estimation of sum and difference

1

First, round off each number to the nearest ten.



Then add.

50 + 80 = 130 So, 47 + 81 ≈ 130.

The value of 47 + 81 is about 130.

Estimate the value of 84 – 42.

First, round off each number to the nearest ten.



Then subtract.

80 – 40 = 40 So, 84 – 42 ≈ 40.

The value of 84 – 42 is about 40.

Let’s estimate the value of 47 + 81 to check the answer.

Ready, Set, Go!

47 ≈ 5081 ≈ 80

84 ≈ 8042 ≈ 40

1

Lesson 6

2

128 ≈ 130The answer is reasonable.


Round off each number to the nearest ten.

Then estimate the value of:

53 + 79 456 – 25

53 ≈ 456 ≈

79 ≈ 25 ≈

+ = – =

So, 53 + 79 ≈ . So, 456 – 25 ≈ .

Round off each number to the nearest hundred.

Then estimate the value of:

634 + 512 2426 – 1296

634 ≈ 2426 ≈

512 ≈ 1296 ≈

+ = – =

So, 634 + 512 ≈ . So, 2426 – 1296 ≈ .

The table lists the items sold at a stationery store.

Estimate the total cost of the eraser and the pencil by rounding off to

the nearest hundred.

Estimate how much more a sticker costs than a ruler by rounding off to

the nearest hundred.

3

4

5

a

a

b

b

a

b

Item Cost

Sticker Rp 850,00

Eraser Rp 920,00

Pencil Rp 890,00

Ruler Rp 610,00


Estimate the value of 64 × 3.

First, round off 64 to the nearest ten.


Then multiply.

60 × 3 = 180So, 64 × 3 ≈ 180.

The value of 64 × 3 is about 180.

Estimate the value of 267 × 7.

First, round off 267 to the nearest hundred.

267 is when rounded off to the nearest hundred.

Then multiply.

× 7 =

So, 267 × 7 ≈ .

The value of 267 × 7 is about .

Estimate the value of 372 ÷ 4.

360 372 400

Then divide.

360 ÷ 4 = 90

So, 372 ÷ 4 ≈ 90.

The value of 372 ÷ 4 is about 90.

64 ≈ 60

267 ≈

372 ÷ 4

372 is nearer to 360 than to 400.

360 ÷ 4400 ÷ 4

Estimation of product and quotient

6

7

8



Then divide.

÷ 8 =

So, 478 ÷ 8 ≈ .

The value of 478 ÷ 8 is about .


Then divide.

÷ 6 =

So, 559 ÷ 6 ≈ .


540 559 600

478 480


÷ 8 =

So, 775 ÷ 8 ≈ .


775

559 ÷ 6

559 is nearer to 540 than to 600.

540 ÷ 6600 ÷ 6


478 ÷ 8 ÷ 8

÷ 8

775 ÷ 8 ÷ 8

÷ 8


9

10

11


Estimate the value of

395 × 6 92 ÷ 3 176 ÷ 5

12a b c

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Ready, Set, Go! Play this game! Carry out this activity · Dr Fong Ho Kheong • Chelvi Ramakrishnan • Gan Kee Soon Singapore Methodology with 100% alignment to the Indonesian syllabus