The Mathematics PSLE Revision Guide (3rd Edition) is a ... · 3rd Edition Michelle Choo Mathematics revision PSLE Worked Examples Revision Guide ISBN 978-981-31-6640-0 97 89813 16640

3rd

Ed

ition

Mich

elle

Ch

oo

Mathem

atics PS

LE Revision G

uide

ISBN 978-981-31-6640-0

9 789813 166400 Michelle Choo BSc, MEd (Maths)

From the creators of

Based on the latestMOE syllabusFor use from 2018

The most complete handbook for PSLE!★ Revise all essential content with comprehensive notes★Reinforce learning at home with parental tips ★Develop exam confidence with practice in latest exam-type questions

3rd Edition

The most complete handbook for PSLE!★ Gain thorough understanding of Science concepts ★ Achieve mastery in application of skills and processes★ Build exam confidence for the PSLE

3rd Edition

Science PSLERevision Guide

By the sole publisher of

Primary Science textbooks

For pupils taking PSLEfrom 2017

Previous editions over 200,000 copies sold

The most complete handbook for PSLE!★ Skill-based practices and a specimen PSLE paper for self-assessment★Clear and easy-to-understand lesson points for quick recall ★Suggested essays as a guide to improve writing skills★Online audio clips for more comprehensive learning

En

glish

PS

LE

Revisio

n G

uid

e (2

nd

Editio

n)

English PSLERevision Guide

2nd Edition

Based on latestPrimaryEnglishsyllabus

The Mathematics PSLE Revision Guide (3rd Edition) is a complete handbook which prepares pupils for all aspects of their PSLE Mathematics paper. This user-friendly book allows pupils to recall concepts learnt and apply them to answer exam-type questions. With this book, pupils are able to revise in an effective and strategic manner, thus helping them to fulfil the goal of attaining better scores in the PSLE.

Features in this book include:

Notes covering all topics for quick and systematic revision

Concept maps provided at the back of the book summarise the notes

Exam-type questions with worked solutions provided

Essential, useful tips and notes to show pupils how to answer similar questions

Short notes to help parents reinforce pupils’ learning or guide pupils through thinking processes

Practice questions train pupils to apply problem-solving heuristics

Practice questions require pupils to think out of the box and use higher order thinking skills such as reasoning and logical deduction

Learn to use heuristics to solve the non-routine questions

Specimen papers based on the latest PSLE format for self-assessment and to develop exam-readiness

Revision Notes

Worked Examples

Parental Tips

Heuristic-based Questions

Non-routine Questions

Exam Practice Papers

Other books in the series:

PSLEMathematics

Revision Guide

(M)MORG_3rdEd_Cover.indd All Pages 9/10/17 3:29 PM

Michelle Choo

From the creators of

Based on the latestMOE syllabusFor use from 2018

3rd Edition

PSLEMathematics

Revision Guide

(M)MORG_3rdEd_TP.indd 1 4/10/17 9:44 AM

BLANK

03(M)PSLE_Rev(3E)_Prelim.indd 10 4/10/17 3:01 am

© 2006, 2009 Marshall Cavendish International (Singapore) Private Limited

© 2014, 2018 Marshall Cavendish Education Pte Ltd

Published by Marshall Cavendish Education

Times Centre, 1 New Industrial Road, Singapore 536196

Customer Service Hotline: (65) 6213 9444

E-mail: [email protected]

Website: www.mceducation.com

First published 2006

Second edition 2009

Third edition 2018

All rights reserved.

No part of this publication may be reproduced, stored in a retrieval system

or transmitted, in any form or by any means, electronic, mechanical,

photocopying, recording or otherwise, without the prior permission

of the copyright owner. Any requests for permission should be

addressed to the Publisher.

Marshall Cavendish is a registered trademark of Times Publishing Limited.

ISBN 978-981-31-6640-0

Printed in Malaysia


© 2018 Marshall Cavendish Education Pte Ltdiv Mathematics PSLE Revision Guide

What Parents Need to Know About the PSLE Mathematics Papers

What is a Good Examination Paper?The PSLE is an assessment that tests everything pupils have learnt in their six years in school and it is used as a gauge to measure a pupil’s performance against the other pupils taking the same examination. A good examination paper is not determined by whether it is easy or difficult, but whether it truly measures what it sets out to do. If a paper is easy and everybody scores high marks, then it is not a good paper as it does not reflect how well a pupil has learnt compared to other pupils.

Format of the PSLE Mathematics PapersThe examination is divided into two papers: Paper 1 (non-calculator) and Paper 2 (calculator). Both papers will be scheduled on the same day with a break between the two papers.

Paper 1 is made up of Booklet A and Booklet B. Booklet A comprises 15 Multiple-choice Questions (MCQs). These are questions that test pupils’ understanding and application of basic concepts. Questions 1 to 10 carry 1 mark each. Questions 11 to 15 carry 2 marks each. Pupils have to shade the correct answer in the Optical Answer Sheet using a 2B pencil. The Optical Answer Sheet is machine marked.

Booklet B comprises 15 Short-answer Questions (SAQs). For these questions, pupils write their answers in the spaces provided. Marks are awarded solely for correct answers and not for working. Questions 16 to 20 carry 1 mark each and they test the basic concepts.

For questions 21 to 30, each question may have one part or two parts, (a) and (b). For all 10 questions, 2 marks are awarded for giving the correct answers. However, if an incorrect answer is given for a one-part question, the examiner will look at the working to see what method the pupil has used. 1 mark will be awarded for correct method. Therefore, it is important for pupils to write clear working to show how they get their answers.

The 15 MCQs carry a total of 20 marks. The 15 SAQs carry a total of 25 marks. Note that the use of calculators is not allowed in Paper 1.

Paper 2 is made up of 17 questions. Questions 1 to 5 are 2-mark SAQs, similar to those in Paper 1. Questions 6 to 17 are Long-answer Questions (LAQs) which carry 3, 4 or 5 marks each. LAQs may have one part or multiple parts.

Unlike SAQs, marks are allocated to working for LAQs. Full marks are awarded only if the pupil gives the correct answer and show the correct method in the working. Therefore, writing clear and meaningful working is important.


Mathematics PSLE Revision Guide v© 2018 Marshall Cavendish Education Pte Ltd

LAQs are usually more challenging than SAQs. Most of the LAQs are word problems. Word problems test the application of concepts in real life contexts. Pupils may need to apply heuristic skills and other thinking skills to solve these problems.

The 5 SAQs carry a total of 10 marks. The 12 LAQs carry a total of 45 marks. Note that the use of calculators is allowed in Paper 2.

Scoring an ‘A’ GradeEvery paper has a mix of easy and difficult questions. A pupil who has prepared well enough for the examination would be able to obtain a pass mark easily. To score an ‘A’ grade, pupils must be able to handle the more difficult questions in Paper 1 and the LAQs in Paper 2. Pupils would need a thorough understanding of the concepts and be able to apply the concepts and the various heuristics to solve the challenging questions.

Tips for Tackling the ExaminationAlways attempt the questions according to the order in the paper. The easiest questions are usually the first few questions of each paper or booklet. Answering these questions first and completing them quickly would give pupils the confidence to do the rest of the paper. Therefore, pupils should never begin Paper 2 by doing the word problems first. These questions need more time to think through.

When pupils encounter a question they have difficulty answering, they should skip it and move on to the next question. They should complete all the questions that they can answer before going back to the ones they skipped earlier.

Some Other AdvicePupils may use the ‘Guess and Check’ method as the last resort to solve problems. When using ‘Guess and Check’, it is important to label the lists, tables, etc. so that the examiners understand the steps in the working.

Most pupils lose some marks due to careless mistakes. This is often a consequence of untidy handwriting, which increases the likelihood of pupils making mistakes somewhere in the working. This often leads to a wrong calculation to get a wrong final answer. Remember that marks are allocated to working for LAQs in Paper 2, and 1 mark is given for correct method but wrong answer for 2-mark SAQs. So it is important to write clear working that examiners can understand. Careless mistakes are also caused by pupils rushing to answer the last few questions when time is running out. Good time management is crucial. Time management tips and other examination strategies are explained in detail on pages 269 to 271.


© 2018 Marshall Cavendish Education Pte Ltdvi Mathematics PSLE Revision Guide

PieChartsInapiechart,thewholecirclerepresentsthetotalquantity.Eachpartofthewholecircle(likeslicesofapie)representsapartofthetotalquantity.

ThepiechartbelowshowshowFrancescaspendsatypicalday.

Good To Know

Inapiechart,theangleatthecentreforeachpartofthecircleisproportionaltothequantityitrepresents.

Thereare24hoursinaday.18×24=3

Francescaspends 1

8ofadayor3hourspractisingthepiano.

Eachpartofthecircleisafractionorpercentageofthewhole.

Thefraction=angle360°

=quantitytotal

3313%

Pianopratice

18

Restandrelax4h

Sleeping

Inschool

Others

Francescaspends4hoursrestingandrelaxing.424×100%= 1

6×100%

=1623%

Shespends 16or162

3%

ofadayrestingandrelaxing.

ThisquartercirclerepresentsthetimeFrancescaspendsinschool.14×24=6

Shespends 14ofadayor

6hoursinschool. Un

it 9

Sta

tist

ics

•

Mathematics PSLE Revision Guide 207© 2018 Marshall Cavendish Education Pte Ltd

How To Use this Book

FRACTIONS

Whatyouneed

toknow

• Part of a whole

• Proper fractions, improper fractions and mixed numbers

• Equivalent fractions

• Comparing and ordering fractions

• Addition and subtraction of fractions

• Multiplication involving fractions

• Division involving fractions

PartofaWhole

A fraction represents a part of a whole.

A pizza was cut into 8 equal slices. Jim ate 3 slices.

The whole circle represents the pizza.

The shaded parts represent the number of slices that Jim ate.

3 out of 8 equal parts are shaded.

So, Jim ate 38 of the pizza.

38

numerator

denominator

38 can be interpreted as 3 ÷ 8.

Unit 2

© 2018 Marshall Cavendish Education Pte Ltd

28 Mathematics PSLE Revision Guide

Worked Examples

1. 400000+20000++90+8=426098

Whatisthemissingnumber?

(1 ) 60(2) 600

(3) 6000(4) 60000 ( )

Solution

Thedigit6isinthethousandsplace.

Thedigit6in426098standsfor6000.

Ans:(3)

2. Whatisthequotientof35350÷7whenroundedtothenear

esthundred?

(1 ) 4900(2) 5000

(3) 5100(4) 5200 ( )

Solution

35350÷7=5050≈5100(tothenearesthu

ndred)

Ans:(3)

3. Howmanyhundredsaretherein3million?

(1 ) 300(2) 3000

(3) 30000(4) 300000 ( )

Solution

3000000÷100=30000

Ans:(3)

Common Error

Somepupilsmightroundoff

firstandthendivide.Readthe

questioncarefully.

Un

it 1

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ole

Nu

mb

ers

•

Mathematics PSLE Revision Guide 15


Addition,Subtraction,MultiplicationandDivisionofDecimals

AdditionofDecimalsFindthesumof0.13and34.07. Whatisthevalueof128.2+54.78?

Decimalpoint1

0 . 1 3+ 3 4 . 0 7

3 4 . 2 0

11 2 8 . 2 0

+ 5 4 . 7 81 8 2 . 9 8

SubtractionofDecimalsFindthedifferencebetween56.97and12.65.

Whatisthevalueof98.2−37.83?

5 6 . 9 7− 1 2 . 6 5

4 4 . 3 2

7 11 109 8 . 2 0

− 3 7 . 8 36 0 . 3 7

128.2isequalto128.20.

At Your Fingertips

Whenaddingorsubtractingdecimalnumbers,thedecimalpointsmustbealignedvertically.

98.2isequalto98.20.

Un

it 3

Deci

mals

•


Dear pupil and parent,The PSLE Mathematics Revision Guide (3rd Edition) is your answer to concise and precise revision for the PSLE. This revision guide strictly follows the latest primary mathematics syllabus issued by the Ministry of Education, and is a structured, all-in-one guide that directs pupils in their revision with the following features:

• What you need to know is a summary of key points pupils must know as stipulated in the syllabus.

• Revision notes are found at the beginning of each unit. These serve as a quick revision of concepts covered in the unit.

• At your fingertips are essential formulae and concepts that are highlighted for pupils to take note of.

• Worked examples are questions with step-by-step solutions. Pupils are guided to work out the questions by utilising important concepts and methods.

• Good to know provides additional information about a topic or concept, which aims to stimulate pupils’ interests in the topic. This complements key concepts covered in the revision notes.

• Common error highlights misconceptions that pupils often have, which in turn lead to careless mistakes. These point out the common mistakes they tend to make.

Quantity Units

Length cm, m, km

Area cm2, m2

Volume cm3, m3, ml, <

Mass g, kg

Times, min, h, day, week, month, year

Area and Perimeter

Four Operations

Rectangles

Length

Breadth

Area of a rectangle= Length × Breadth

Perimeter of a rectangle= 2 × Length + 2 × Breadth

Triangles

Height

Base

Base

BaseBase

Area of a triangle= 12 × Base × Height

Perimeter of a triangle= Sum of lengths of the 3 sides of the triangle

Perimeter of Rectilinear Figures

Areas of Figures Drawn in Square Grids

To find the perimeter of a rectilinear figure, add up the lengths of all sides of the figure.

The area of the figure above is 15 square units.

Squares

Area of a square= Length × Length

Perimeter of a square= 4 × LengthLength

Circles

A O

B

The perimeter of a circle is the circumference.

Area of a circle = π × r × rCircumference of a circle = π × d= 2 × π × r

SemicirclesA O

B

A semicircle is 12 of a circle.Area of a semicircle = 12 × π × r × rPerimeter of a semicircle = 12 × 2 × π × r + r + r

Quarter circlesA O

B

A quarter circle is 14 of a circle.Area of a quarter circle = 14 × π × r × rPerimeter of a quarter circle = 14 × 2 × π × r + r + r

O is the centre of the circle.AB is a diameter d.OA = OB

= Radius r

Volume

Cuboids

BL

H

Volume of a cuboid= Length × Breadth × Height

Cubes

LL

L All faces are squares.Volume of a cube= Length × Length × Length

Conversion of Units

1 day = 24 h1 week = 7 days

1 year = 12 months

1 h = 60 min

1 min = 60 s

1 min = 160 h

1 s = 160 min

1 km = 1000 m1 m = 100 cm

1 m = 0.001 km1 cm = 0.01 m

1 kg = 1000 g 1 g = 0.001 kg

1 < = 1000 ml = 1000 cm3

1 ml = 0.001 < = 1 cm3

Units of Measurement

MeASUReMenT

To add, subtract, multiply or divide quantities:

Method 1: Work out each unit separately

E.g. 2 m 60 cm + 3 m 70 cm = 5 m 130 cm = 6 m 30 cm

Method 2: Convert to a common unit

E.g. 2 m 60 cm + 3 m 70 cm = 260 cm + 370 cm = 630 cm = 6 m 30 cm

© 2018 M

arshall Cavendish Education Pte Ltd372

Math

ematics PSLE R

evision

Gu

ide


Mathematics PSLE Revision Guide vii© 2018 Marshall Cavendish Education Pte Ltd

NON-ROUTINE QUESTIONSUnit 12

Parental Tip

Non-routine

questions

areunfamiliara

pplicationq

uestionstha

trequirehig

herorder

thinkingsk

ills.Theycan

besolvedu

singheurist

icsorbyun

conventiona

lmethods.

Usuallysuc

hquestions

arebestw

orkedoutb

ymakinginfere

ncesthroug

hlogical

deductions

fromthequestio

ns.

Worked Examples

Davidwass

trollingalong

apathplan

tedwithtre

esataneq

ualdistance

apart.

Hetook22m

intostrollfr

omthe1sttree

tothe12tht

ree.Atwhic

htreewould

David

beafterstro

llingfor120m

in?

Solution

Strategy:Dr

awadiagra

m.

12th

1st

22min

Numberofinterv

alsfor1sttre

eto12thtree

=11

Timetakentos

trollfromonet

reetoanoth

er

=22÷11

=2min

Numberofinterv

alsafterstr

ollingfor120

min

=120÷2

=60

Numberoftrees

=60+1

=61

Davidwould

beatthe6

1sttreeafte

rstrollingfo

r120min.

Drawingad

iagramhelps

ustovisua

lise

andunders

tandthepro

blembetter.

Fromthediagram

,weseetha

tthetotal

numberoftrees

isalways1

morethan

thetotalnu

mberofinterv

alsbetween

thetrees.


264 Mathematics PSLE Revision GuideThe use of calculators is NOT allowed in this paper.Questions 1 to 10 carry 1 mark each. Questions 11 to 15 carry 2 marks each. For each question, four options are given. One of them is the correct answer. Make your choice (1, 2, 3 or 4) and shade your answer on the Optical Answer Sheet.

(20 marks)1. Find the value of 35 − 5 × 2 + 20 ÷ 4. ( 1 ) 10 (2) 20 (3) 30 (4) 50

2. Find the value of 3x + 2x4 − 15 when x = 8.

( 1 ) 11 12 (2) 13

(3) 17 12 (4) 30

3. In the figure below, AD is parallel to HE, and HE is perpendicular to BF. Which of the following is not correct?

B

D

E

F

GHA

e

fgc hd

b

a

(1 ) b = c (2) c + d = f (3) a + c + d = g (4) 90° − c − d = b

EXAM PRACTICE 1Paper 1 45

Duration: 1 h


274 Mathematics PSLE Revision Guide

Symmetry

Figuresthatcanbedividedintoequalhalvesbylinesofsymmetryareknownassymmetricfigures.

Thefiguresbelowhave1lineofsymmetry.

Lineofsymmetry

Thefigurebelowhas2linesofsymmetry. Thestarhas5linesofsymmetry.

Thefiguresbelowarenon-symmetric.

Maths At HomeUsecolouredpapers,foldthemintohalvesorquarters.Cutwithapairofscissors.

Thenunfold.

Whatdoyounotice?

Parental Tip

Helpyourchildtoidentifythedottedlineswhichformthelinesofsymmetryforthesecut-outs.

Placearectangularmirroronthedottedlinetocheckifthefiguresaresymmetric.

Un

it 5

Geo

metr

y

•


HEURISTICS-BASED QUESTIONS

Unit 11

What you need to know• Actitout• Drawadiagram• Drawamodel• Beforeandafter• Useanequation• Guessandcheck• Lookforpatterns• Makeasupposition• Makeasystematiclist• Simplifytheproblem• Solvepartoftheproblem• Restatetheproblem• Workbackwards

Act It Out WorkedExample1Anetofacubeisshownbelow.

Un

it 1

1

Heu

rist

ics-

Base

d Q

uest

ion

s •

Mathematics PSLE Revision Guide 237


• Heuristics-based questions require pupils to apply heuristic skills to solve problems. MOE has stressed the need for this category of questions. The PSLE Mathematics Revision Guide (3rd Edition) has an entire chapter dedicated to heuristics-based questions and provides up to 3 worked examples for each heuristic. Similar practice questions are given on that heuristic as reinforcement.

• Non-routine questions are challenging questions that require thinking out of the box. Worked examples and practice questions are provided to give pupils more practice.

• Maths at home provides pupils with hands-on activities that reinforce concepts that are difficult to visualise.

• Parental tips provide suggestions to parents on how they can facilitate their child’s thinking process.

• Exam practice papers are provided to simulate the PSLE papers. These papers follow the latest format of the PSLE Mathematics papers.

Quantity Units

Length cm, m, km

Area cm2, m2

Volume cm3, m3, ml, <

Mass g, kg

Times, min, h, day, week, month, year

Area and Perimeter

Four Operations

Rectangles

Length

Breadth

Area of a rectangle= Length × Breadth

Perimeter of a rectangle= 2 × Length + 2 × Breadth

Triangles

Height

Base

Base

BaseBase

Area of a triangle= 12 × Base × Height

Perimeter of a triangle= Sum of lengths of the 3 sides of the triangle

Perimeter of Rectilinear Figures

Areas of Figures Drawn in Square Grids

To find the perimeter of a rectilinear figure, add up the lengths of all sides of the figure.

The area of the figure above is 15 square units.

Squares

Area of a square= Length × Length

Perimeter of a square= 4 × LengthLength

Circles

A O

B

The perimeter of a circle is the circumference.

Area of a circle = π × r × rCircumference of a circle = π × d= 2 × π × r

SemicirclesA O

B

A semicircle is 12 of a circle.Area of a semicircle = 12 × π × r × rPerimeter of a semicircle = 12 × 2 × π × r + r + r

Quarter circlesA O

B

A quarter circle is 14 of a circle.Area of a quarter circle = 14 × π × r × rPerimeter of a quarter circle = 14 × 2 × π × r + r + r

O is the centre of the circle.AB is a diameter d.OA = OB

= Radius r

Volume

Cuboids

BL

H

Volume of a cuboid= Length × Breadth × Height

Cubes

LL

L All faces are squares.Volume of a cube= Length × Length × Length

Conversion of Units

1 day = 24 h1 week = 7 days

1 year = 12 months

1 h = 60 min

1 min = 60 s

1 min = 160 h

1 s = 160 min

1 km = 1000 m1 m = 100 cm

1 m = 0.001 km1 cm = 0.01 m

1 kg = 1000 g 1 g = 0.001 kg

1 < = 1000 ml = 1000 cm3

1 ml = 0.001 < = 1 cm3

Units of Measurement

MeASUReMenT

To add, subtract, multiply or divide quantities:

Method 1: Work out each unit separately

E.g. 2 m 60 cm + 3 m 70 cm = 5 m 130 cm = 6 m 30 cm

Method 2: Convert to a common unit

E.g. 2 m 60 cm + 3 m 70 cm = 260 cm + 370 cm = 630 cm = 6 m 30 cm

© 2018 M

arshall Cavendish Education Pte Ltd372

Math

ematics PSLE R

evision

Gu

ide

• Concept maps are useful for pupils when doing a quick revision prior to their examination. These are summaries of key concepts for each chapter.


© 2018 Marshall Cavendish Education Pte Ltdviii Mathematics PSLE Revision Guide

Contents

Unit 1 Whole Numbers 1

Unit 2 Fractions 28

Unit 3 Decimals 52

Unit 4 Measurement 74

Unit 5 Geometry 107

Unit 6 Average, Rate and Speed 138

Unit 7 Ratio 157

Unit 8 Percentage 180

Unit 9 Statistics 204

Unit 10 Algebra 224

Unit 11 Heuristics-Based Questions 237

Unit 12 Non-Routine Questions 264


Mathematics PSLE Revision Guide ix© 2018 Marshall Cavendish Education Pte Ltd

Concept Maps

Whole Numbers 367

Fractions 368

Decimals 369

Geometry 370

Measurement 372

Average, Rate and Speed 373

Ratio 373

Statistics 373

Percentage 374

Examination Tips for the Pupil 269

PSLE Exam Practice 1 273

PSLE Exam Practice 2 295

Solutions 317


BLANK


WHOLE NUMBERS

Unit 1

What you need to know• Countinginhundredthousandsupto1million• Numbernotationandplacevalues• Comparingandorderingnumbersupto10million• Oddandevennumbers• Approximationandestimation• Factorsandmultiples• Multiplicationanddivision• Orderofoperations

Counting in Hundred Thousands up to 1 Million

100000200000

300000400000

500000600000

700000800000

9000001000000

0

Onehundredthousand,twohundredthousands,threehundredthousands,fourhundredthousands,...

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04(M)PSLE_Rev(3E)_U1.indd 1 3/10/17 11:26 am

Number Notation and Place Values

ReadingNumbersLetuslookatthenumber,1234567.

Number Words

1234567 Onemillion,twohundredandthirty-fourthousand,fivehundredandsixty-seven.

PlaceValues

1 2 3 4 5 6 7

7 Ones 7

6 Tens 60

5 Hundreds 500 4 Thousands 4000 3 Tenthousands 30000 2 Hundredthousands 200000 1 Million 1000000

Thereare10hundredthousandsin1million.

Thereare100000tensin1million.

Howmanyhundredthousandsaretherein1million?

Howmanytensaretherein1million?

1 000 000 can also be written as

1 million

10 hundredthousands

100 tenthousands

1000 thousands

10000 hundreds

100000 tens

Letusfindoutwhateachdigitstandsfor.

© 2018 Marshall Cavendish Education Pte Ltd2 Mathematics PSLE Revision Guide


Comparing and Ordering Numbers up to 10 Million

ComparingNumbersLetusfindoutwhichnumberisgreater:456789or457698

HundredThousands

TenThousands Thousands Hundreds Tens Ones

4 5 6 7 8 9

4 5 7 6 9 8

7thousandsisgreaterthan6thousands.So,457698isgreaterthan456789.

Odd and Even Numbers

OddNumbersOddnumbersarenumbersthatcannotbedividedexactlyby2.1,3,5,7,9,11and13areoddnumbers.

EvenNumbersEvennumbersarenumbersthatcanbedividedexactlyby2.2,4,6,8,10and12areevennumbers.

Whenwecomparenumbers,welookattheplacevalues.Sincethedigitsinthehundredthousandsplaceandtenthousandsplacearethesame,wecomparethedigitsinthethousandsplace.

29,63,103,999and1245areotherexamplesofoddnumbers.

34,76,258,554and1000areotherexamplesofevennumbers.

At Your Fingertips

Oddnumbersalwaysendwithdigits1,3,5,7or9.Evennumbersalwaysendwithdigits2,4,6,8or0.

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it 1

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ole

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Approximation and Estimation

RoundingNumbersRoundingtotheNearestTen

33 38

3530 40

Both33and38arebetween30and40.33isnearerto30thanto40.38isnearerto40thanto30.

Therefore,33becomes30whenroundedtothenearestten,38becomes40whenroundedtothenearestten.

30

35

3 3

3 8

40

Thesymbol≈means‘approximatelyequalto’.

33≈30(tothenearestten)38≈40(tothenearestten)

At Your Fingertips

Forroundingtothenearest ten,followthisrule:Whentheones digitis5ormore,weroundup.Whentheones digitis4orless,werounddown.

© 2018 Marshall Cavendish Education Pte Ltd4 Mathematics PSLE Revision Guide


Documents

The Mathematics PSLE Revision Guide (3rd Edition) is a ... · 3rd Edition Michelle Choo Mathematics revision PSLE Worked Examples Revision Guide ISBN 978-981-31-6640-0 97 89813 16640