maths 5a · 2 rehna spent 1 5 of her money on 8 pencils and 2 markers. the cost of each marker is...
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Maths 5A3rd Edition
Pupil’s Book
Dr Fong Ho Kheong • Gan Kee Soon • Chelvi Ramakrishnan
•AP
PRO
VE
DBY MINISTRY OF EDUCATIO
N•
for use from 2017–2021
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PrefaceMy Pals Are Here! Maths (3rd Edition) is a comprehensive, task-based and learner-centred programme designed to provide pupils with a solid foundation in mathematics and opportunities to become efficient problem solvers.
My Pals Are Here! Maths (3rd Edition) continues to make learning mathematics fun and rewarding through the use of engaging illustrations, photographs, hands-on activities and interactives that help reinforce and consolidate learning for pupils of different abilities.
A calculator may be used when appears.
For the Pupil:
Challenge yourself to solve non-routine questions by applying relevant heuristics and thinking skills in Put On Your Thinking Cap!
Workbook A:Put On Your Thinking Cap!pages 83–84Review 2, pages 85–88
Put On Your Thinking Cap!Put On Your Thinking Cap!
1 Annacycledfromschooltohome.Shestoppedbythepostoffice,thenwentbacktothemalltobuylunch.Shethenheadedhomefromthemall.Use the following clues to find how far Anna’s home is from her school.
School Mall Postoffice Home • The post office is 2 25 km from Anna’s school. • The mall is 1 1
10kmfromthepostoffice. • Anna’s home is 2 310kmfromthemall.
2 Rehnaspent 15 of her money on 8 pencils and 2 markers. The cost of each
markeristwicethecostofeachpencil.Sheboughtsomemoremarkerswith58ofherremainingmoney.HowmanymarkersdidRehnabuyaltogether?
3 Andreahasaboxofcoins.Shewrotedownthenumberofcoinsshehasbutspilledherdrinkoverherpaper.
Coin Number of Coins20¢
950¢
However,sheknowsthat 310 of her coins are 50¢ and the rest are 20¢ coins. Also, she has more than 50 but fewer than 100 coins. Howmanycoinsdoesshehave?
Chapter 5 Fractions:WordProblems 10108_(M)MPaHTB5A_05.indd 101
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Big Idea
The area of a triang
le is given by
half the product of
a base and the
corresponding heig
ht.
Any side of a triangle can be its base.
The height is perpendicular to the base.
Example
C
AB
Z base
height
Base and Height
The area of a triangle is half the area of a rectangle with the same ‘base’ and
‘height’ or 12 3 base 3 height.
F
E
G
D2 cm
4 cm
Area of triangle DEF
5 12 3 Area of rectangle DEFG
5 12 3 EF 3 DE
5 12 3 base 3 height
5 12 3 4 3 2
5 4 cm2
Finding the Area
We can find the area of a composite figure by dividing it into rectangles, squares or triangles.
4 cm
3 cm
8 cm
A
B
CD
E
Area of figure ABCDE5 Area of rectangle
BCDE 1 Area of triangle ABE
Area of rectangle BCDE5 8 3 4 5 32 cm2
Area of triangle ABE
5 12 3 8 3 3
5 12 cm2
Area of the figure5 32 1 125 44 cm2
Composite Figures
Area of a Triangle
Chapter Wrap-UpChapter Wrap-Up
Chapter 6 Area of a Triangle116
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Consolidate the concepts you have learnt in each chapter in Chapter Wrap-Up!
NEW!
TRY
1A Multiply213by3.E
xpressyouranswerasamixednumber.
Then,checkyouranswerusingacalculator.
2 1333
213335
TRY
1B Multiply.Expressyouranswerinitssimplestform.
a 356325 b 432355
c 134385 d 2835275
e 2593165 f 1237 9105
Workbook A:Practice 3, pages 55–56
Maths SharingExpressamixednumberasaproduct.
Themodelshows4 12.
a Expressthismixednumberasaproductofanothermixednumberanda
wholenumber.
4 125 32
b Usethesamemethodtofindthemissingmixednumberbelow.
8 145 32
Sharewithyourpartnerhowyoufoundthe
missingmixednumbers.
Chapter 4 MultiplicationofWholeNumbers,FractionsandMixedNumbers
82
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Practise new concepts learnt in parallel questions with help from your teacher in TRY!
NEW!
Share your thoughts with your teachers, create your own mathematics questions and become aware of your own mathematical thinking in Maths Sharing!
02_(M)MPaHTB5A_Preface.indd 2 18/8/16 9:32 am
Lesson
3 Order of Operations
Order of operations
L
EARN
1 Forthefollowingproblems,AllyandJoesolvedthemdifferently.Whoiscorrect? a Nelliehad10stickers.Shegaveaway4andbought5more.HowmanystickersdidNelliehaveintheend? 1024155?
Ally’s solution:102456615511Nelliehad11stickersintheend.
Joe’s solution:41559102951Nelliehad1stickerintheend.
Use tochecktheanswer.
givenaway bought 102415 5615 511
Nelliehad11stickersintheend.
AllyandJoeworkedoutthevalueoftheexpression81204422.Ally’s answer was 5. Joe’s answer was 11.Whoseansweriscorrect?Explain.
Before you learn ...
Lesson 3 Order of Operations 35
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1
Theratioofthenumberofredcapstothenumberofblackcaps
is : .
Theratioofthenumberofblackcapstothenumberofredcaps
is : .
2 Findthemissingnumbers.
a A
B
b A
B
A:B5 : A:B5 :
3 Expresseachratioinitssimplestform.
a 9:65 b 8:20:165
4 Findthemissingnumbers.
a 7:8521:
b 42:495 :7
c 4:3:7520: :
d 40:55:155 : :3
Chapter 7 ReviewChapter 7 Review
Chapter 7 Ratio142
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NEW!Assess understanding when pupils apply concepts learnt in Review.
Introduce concepts through context-based tasks in Before you learn. At the end of each task, a question is posed to develop pupils’ creative and critical thinking skills.
NEW!Multiplication of Whole Numbers, Fractions
and Mixed Numbers
This recipe serves 1. How can
I f ind the amount of each
ingredient for 3 servings?
4Chapter
1 ProductofaFractionand
aWholeNumber
2 ProductofTwoFractions
3 ProductofaMixedNumber
andaWholeNumber
Lessons
Big Idea
Whole numbers,
fractions and mixed
numbers can be
multiplied in any
combination.
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Use scenarios pupils can relate to in the chapter openers to capture their interest, provide an engaging introduction to the topics and jump-start learning.
Teach concepts in concise steps using real-life contexts, manipulatives and meaningful visuals in LEARN.
NEW!For the Teacher:
Solvewordproblems.hands-On activity
LearN
Workingroups.Station 1 1 Readthewordproblem.Drawamodelfortheproblem. example
Aretailersold5vacuumcleaners.2ofthevacuumcleanerscost$659eachandtheotherscost$478each.Howmuchmoneydidtheretailermakefromthesaleofthe5vacuumcleaners?
$659
?
$478
2 Estimatetheanswer.3 Usethemodeltosolvetheproblem.4 Comparetheanswersin 2 and 3 tocheckforreasonableness.5 Switchroles.Repeat 1 to 4 withtheseproblems. a Marybought24boxesofbeads.Eachboxcontained245beads.
Therewere2184redbeadsandtherestwerebluebeads.Sheusedallthebluebeadstomake42bracelets.Howmanybluebeadswereusedforeachbracelet?
b Farahbaked72cupcakesand55muffins.Shesold22cupcakes.Shethenpackedtheremainingcupcakesequallyinto5boxes.Shegaveaway2boxesofcupcakes.Howmanycupcakesdidshehaveleft?
Chapter 2 OperationsofWholeNumbers44
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Carry out Hands-On Activity to promote active and collaborative learning. Where possible, pupils will complete station-based activities in rotating groups to best utilise class time.
02_(M)MPaHTB5A_Preface.indd 3 18/8/16 9:32 am
CONTENTS1 WholeNumbers 6
Lesson1 Numbersto10Million 7
2 OperationsofWholeNumbers 16Lesson1 Multiplyingby10,100,1000andTheirMultiples 17
Lesson2 Dividingby10,100,1000andTheirMultiples 27 Lesson3 OrderofOperations 35 Lesson4 SolvingWordProblems 41
3 FractionsandMixedNumbers 53 Lesson1 FractionsandDivision 54 Lesson2 AdditionofMixedNumbers 60 Lesson3 SubtractionofMixedNumbers 63
4 MultiplicationofWholeNumbers,FractionsandMixedNumbers 70
Lesson1 ProductofaFractionandaWholeNumber 71 Lesson2 ProductofTwoFractions 74
Lesson3 ProductofaMixedNumberand aWholeNumber 81
03_(M)MPaHTB5A_Contents.indd 2 19/7/16 7:44 am
5 Fractions:WordProblems 86 Lesson1 SolvingWordProblems 87 6 AreaofaTriangle 102 Lesson1 AreaofaTriangle 103 Lesson2 CompositeFigures 110
7 Ratio 118 Lesson1 FindingRatios 119 Lesson2 EquivalentRatios 124 Lesson3 ComparingThreeQuantities 128 Lesson4 SolvingWordProblems 131
8 VolumeofCubesandCuboids 146 Lesson1 VolumeofaSolid 147 Lesson2 DrawingCubesandCuboids 151 Lesson3 VolumeofaCubeandaCuboid 159 Lesson4 VolumeofaLiquid 164
03_(M)MPaHTB5A_Contents.indd 3 19/7/16 7:44 am
Whole Numbers1Chapter
1 Numbersto10MillionLessonthe next two place values after ten thousands are hundred thousands and millions.
Big Idea
Type FloorArea(m2) Price($)2-bedroom 70 11700003-bedroom 93 12090004-bedroom 123 15990005-bedroom 150 2080000
How do I read $1 209 000?
In the 1980s, your grandfather bought a 3-bedroom condominium for $450 000. How much does a 3-bedroom condominium cost now?
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Lesson
1 Numbers to 10 Million
Reading and writing 6-digit numbers
Recall
Count in thousands.
1000100010001000 1000100010001000 10001000 10 000
10 thousands 5 1 ten thousand
L
EARN
1A Count in ten thousands.
10 000 10 000 10 000 10 000 10 000 10 000 10 000 10 000 10 000 10 000 100 000
10 ten thousands 5 1 hundred thousand
1 ten thousand 5 10 thousands 10 ten thousands 5 100 thousands So, 1 hundred thousand 5 100 thousands.
L
EARN
1B Count in hundred thousands.
1 000 000100 000 100 000 100 000 100 000 100 000 100 000 100 000 100 000 100 000 100 000
10 hundred thousands 5 1 million
1 hundred thousand 5 100 thousands 10 hundred thousands 5 1000 thousands So, 1000 thousands 5 1 million.
There are 147 853 people in a queue. Use 11001000
10 000100 000
1 000 00010 to count aloud
and show the number of people in the queue.
Before you learn ...
10 000, 20 000, 30 000, 40 000, 50 000, 60 000, 70 000, 80 000, 90 000, 100 000
100 000, 200 000, 300 000, 400 000, 500 000, 600 000, 700 000, 800 000, 900 000, 1 000 000
Lesson 1 Numbers to 10 Million 7
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LearN
1C Countusing 11001000
10 000100 000
1 000 00010 .
100 000
100 000
100 000
100 000
100 000
10 000
10 000
10 000
1000
1000
1000
1000
100
100
100
100
100
100
100
100
100
10
10
1
1
1
1
1 1
hundredthousands
ten thousands thousands hundreds tens Ones
5 3 4 9 2 6
standsfor5 hundred thousands500000
standsfor3 ten
thousands30000
standsfor4 thousands
4000
standsfor9 hundreds
900
standsfor2 tens20
standsfor6 ones
6
534926
fivehundredandthirty-fourthousand ninehundredandtwenty-six
fivehundredandthirty-fourthousand,ninehundredandtwenty-six
Chapter 1 Whole Numbers8
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trY
1a Writeinnumeralsandinwords.
100 000
100 000
100 000
100 000
100 000
10 000
10 000
10 000
10 000
10 000
10 000
10 000
1000
1000
1000
100
100
100
100
100
100
100
100
100
10
10 1
Numerals:
Words:
trY
1B Writeinfigures.
a sixhundredandseventy-threethousand,ninehundredandeleven
b fivehundredandeighteenthousandandfour
c twohundredthousand,onehundredandsix
trY
1C Writeinwords.
a 320176
b 438830
c 906095
trY
1D Findthemissingnumbers.
a 23415652340001
b 3182055 1205
c 4820001 5482670
d 17805600780
Lesson 1 Numbers to 10 Million 9
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reading and writing 7-digit numbers L
earN
1a Countinmillions.
1 000 000 1 000 000 1 000 000 1 000 000 1 000 000 1 000 000 1 000 000 1 000 000 1 000 000 1 000 000
10000000tenmillions
L
earN
1B Countusing 11001000
10 000100 000
1 000 00010 .
1 000 000
1 000 000
1 000 000
100 000
100 000
100 000
100 000
10 000
10 000
10 000
10 000
10 000 10 000
1000
1000
100
100
100
100
100
100
100
10
10
10
10
10 1
Millions hundredthousands
ten thousands thousands hundreds tens Ones
3 4 6 2 7 5 1
standsfor3 millions3000000
standsfor4 hundred thousands400000
standsfor6 ten
thousands60000
standsfor2 thousands
2000
standsfor7 hundreds
700
standsfor
5 tens50
standsfor
1 one1
threemillion sevenhundredandfifty-one3462751
fourhundredandsixty-twothousand threemillion,fourhundredandsixty-twothousand,
sevenhundredandfifty-one
MrKrishnandonated$10000000toacharity.Use 11001000
10 000100 000
1 000 00010 tocount
aloudandshowtheamountofmoneyhedonated.
Before you learn ...
1 000 000, 2 000 000, 3 000 000, 4 000 000, 5 000 000, 6 000 000, 7 000 000, 8 000 000, 9 000 000, 10 000 000
Chapter 1 Whole Numbers10
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Readandwritelargenumbers.hands-On activity L
earN
Workingroups.
1 Use 11001000
10 000100 000
1 000 00010 toshow458712.
2 Writeinwords.
example
3 Switchroles.Repeat 1 and 2 withthesenumbers.
a 543201 b 359490 c 1645027 d 2000546
trY
1a Writeinfiguresandinwords.
1 000 000
1 000 000
1 000 000
10
10
100
100
100
100
100 000
100 000
100 000
100 000
100 000 100 000
10 000
10 000
10 000
10 000
10 000
10 000
10 000
10 000
10 000
1
1
1
1
1
Figures:
Words:
Lesson 1 Numbers to 10 Million 11
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trY
1B Writeinfigures.
a threemillion,fivehundredandsixty-seventhousandandforty-five
b fourmillion,sixhundredandfivethousand,threehundredand seventy-nine
c sixmillion,threehundredandtwenty-onethousand,fivehundredand four
trY
1C Writeinwords.
a 1234567
b 8090909
c 2653870
trY
1D Findthemissingnumbers.
a 2300598520000001 1598
b 42163505 12160001350
c 50000001 194655081946
d 90000001 12059106020
Maths Sharing FindexamplesofnumbersinthemillionsfromtheInternetanddevelopasenseofthesizeof1million.
1 SearchtheInternetfortheseatingcapacityoftheSingaporeIndoorStadium. Imaginethatanewindoorstadiumwithaseatingcapacityof1000000
willbebuilt. HowmanytimesaslargeastheSingaporeIndoorStadiumwillthenew
indoorstadiumbe? Discuss.
Chapter 1 Whole Numbers12
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1 Writeinnumerals.
a threehundredandseventy-sixthousand,twohundredandfourteen
b sevenmillion,fourhundredandfiftythousand,ninehundredand eighty-six
2 Writeinwords.
a 872649
b 5380170
3 Findthemissingnumbers.
a 57831255780001
b 46231805 16230001180
c 16085210608
d 900000014080001 59408326
2 LookuptheInternetforthreedifferentexamplesofnumbersinmillionsupto10million.
example ThepopulationofSingaporewas5076700in2010.
Discuss.
Workbook a:Chapter 1 review, page 7Maths Journal, page 8
Workbook a:practice 1, pages 5–6
Chapter 1 reviewChapter 1 review
Chapter 1 Whole Numbers 13
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reading
hundredthousands
ten thousands thousands hundreds tens Ones
6 3 4 0 5 8
sixhundredandthirty-fourthousand fifty-eight
sixhundredandthirty-fourthousandandfifty-eight
WritingIn numerals or figures:634058In words:sixhundredandthirty-fourthousandandfifty-eight
reading and Writing 6-digit Numbers
Whole Numbers
reading
onehundredandfifty-twothousand
eightyfourmillion
Millions hundredthousands
ten thousands thousands hundreds tens Ones
4 1 5 2 0 8 0
fourmillion,onehundredandfifty-twothousandandeighty
WritingIn numerals or figures:4152080In words:fourmillion,onehundredandfifty-twothousandandeighty
reading and Writing 7-digit Numbers
Big IdeaThenexttwop
lacevaluesafter
tenthousandsarehundredt
housands
andmillions.
Chapter Wrap-UpChapter Wrap-Up
Chapter 1 Whole Numbers14
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Workbook a:put On Your thinking Cap!pages 9–10
put On Your thinking Cap!put On Your thinking Cap!
1 Carinawantstosolvea7-digitsecretcodetoasafe. UsethecluestohelpCarinasolvethesecretcode.
• Allsevendigitsaredifferent. • Thedigitinthetenthousandsplaceis5. • Thedigitinthethousandsplaceistwicethedigitinthe
hundredthousandsplace. • Thedigitintheonesplaceis2morethanthedigitinthemillionsplace. • Thedigitinthemillionsplaceis8lessthanthedigitinthe
hundredsplace. • Thedigitinthemillionsplaceis1lessthanthedigitinthetensplace.
Whatisthesecretcode?
2 a Withoutaddingthe99stogether,findthevalueofeachofthefollowing.
i 99+99
ii 99+99+99+99+99+99 Whatisthevalueofthedigitintheonesplaceineachcase?
b Findthesmallestnumberof99sthatmustbeaddedtogeta1intheonesplace.
c Withoutmultiplying99by45,explainhowyoucanfindthesumof45ninety-nines.
Chapter 1 Whole Numbers 15
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