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10 ACMNA073 Number and place value • Apply place value to partition, rearrange and regroup numbers to at least tens of thousands to assist calculations and solve problems. ACMNA083 Patterns and algebra • Use equivalent number sentences involving addition and subtraction to find unknown quantities.
1 JerryandJosiefinishedtheirmathstests.
a Marktheirwork. bGiveeachofthemamark. c Rewritetheonesthatarewrongandworkoutthecorrectanswer.
2 Completethesenumberpatterns.
a 7–2=______ b 9–4=______ c 8–3=______ d 9–7=______
70–20=______ 90–______=______ ______–______=______ ______–______=______
700–200=______ 900–______=______ ______–______=______ ______–______=______
e 5–2=3 f 7–4=______ g 8–4=______ h 6–3=______
15–2=______ 17–4=______ 18–4=______ 16–3=______
25–2=______ 27–4=______ 28–4=______ 26–3=______
85–2=______ 67–4=______ 58–4=______ 96–3=______
Two-digit subtractionTwo-digit subtraction
64–31______________
72–30______________3 3 4 0
99–63______________
59–15______________3 5 4 4
36–15______________
47–27______________2 1 2 7
Josie78
–23______________
69–15______________4 5 5 4
85–23______________
77–45______________6 2 4 2
59–27______________
48–16______________2 2 3 2
Jerry
Mark__________ Mark__________
ghost houseLab 4Lab 4
2-digit algorithms
11ACMNA073 Number and place value • Apply place value to partition, rearrange and regroup numbers to at least tens of thousands to assist calculations and solve problems. ACMNA083 Patterns and algebra • Use equivalent number sentences involving addition and subtraction to find unknown quantities.
5 FarmerFredhad64sheep.Howmanywereleftwhenhesold39?
6 Carolhad880jellybeans.Shewassickwhensheate132.Howmanywereleft?
1 UsestrategyA.
a 53–28=____________________ b 64–29=64–_____+_____
=_____ =_____
c 46–19=46–_____+_____ d 85–57=85–_____+_____
=_____ =_____
e 97–68=97–_____+_____ f 73–36=73–_____+_____
=_____ =_____
2 UsestrategyB.
a 67–43=67–40–3 b 91–52=91–_____–_____
=_____ =_____
c 52–24=52–_____–_____ d 75–31=75–_____–_____
=_____ =_____
e 80–33=80–_____–_____ f 41–24=41–_____–_____
=_____ =_____
3
a
b
4
a
b
Subtraction strategiesSubtraction strategies
StrategyA64–18=64–20+2=46
StrategyB71–24=71–20–4=47
Partition91is90and1.Takeaway90
thentakeawayanother1.
Checkanswersbycountingon.
27–
38
7356 64 49 76 62 81 50
32–
53
9161 70 62 87 74 90 83
Challenge!Makeupasubtractionproblemaboutkiteswheretheansweris37.
53-30+2
Mixed
12 ACMNA073 Number and place value • Apply place value to partition, rearrange and regroup numbers to at least tens of thousands to assist calculations and solve problems. ACMNA083 Patterns and algebra • Use equivalent number sentences involving addition and subtraction to find unknown quantities.
Subtraction on a number lineSubtraction on a number line Touseanumberlineforsubtractionstartfromtheright.72–37Youcanuselittlejumps
orbigjumps.
53
71
85
1 a 16–9=________ b 15–8=________
c 14–6=________ d 12–7=________
e 11–5=________ f 16–8=________
g 15–9=________ h 13–6=________
i 14–5=________ j 17–8=________
2 Usethenumberlines.
a 53–26=________
b 71–43=________
c 85–37=________
d 92–48=________
e 80–35=________
f 264–149=_______
g 376–123=_______
h 457–243=_______
3 Jinlovesolives.Hehad73jarsinthepantry.Thievesbrokeinandstole47jars.
a Howmanydidhehaveleft?________
b Howdidyouworkoutyouranswer?________________________________________________________
__________________________________________________________________________________________________
c Showanotherway.___________________________________________________________________________
d Whichwaywasbest?_____________________
e Howcanyoucheckifyouarecorrect?_____________________________________________________
Strategies –
–1 –10
7262524235
–1 –1 –5 –30
35 37 42 72
13ACMNA073 Number and place value • Apply place value to partition, rearrange and regroup numbers to at least tens of thousands to assist calculations and solve problems. ACMNA080 Money and financial mathematics • Solve problems involving purchases and the calculation of change to the nearest five cents with and without digital technologies.
3-digit subtraction
2 Changefrom$1?
3
Three-digit subtractionThree-digit subtraction
WorkbackwardsIfIsubtract13fromanumber,thendoubletheanswer,Iget28.
Whatisthenumber?
1 Usethehundredsquaretohelp.
a 100–56=________,56+________=100
b 100–23=________,23+________=100
c 100–49=________,49+________=100
d 100–64=________,64+________=100
e 100–11=________,11+________=100
f 100–77=________,77+________=100
a 346–125_________
_________
b 877–542_________
_________
c 539–413_________
_________
d 621–320_________
_________
e 959–426_________
_________
f 148–23__________________
g 273–153_________
_________
h 759–532_________
_________
i 485–165_________
_________
j 907–506_________
_________
k 986–144_________
_________
l 890–770_________
_________
m 679–238_________
_________
n 748–341_________
_________
o 485–21__________________
83c
37c
45c
68c
79c
a c e
b d
14
Problem solvingProblem solving
ACMNA073 Number and place value • Apply place value to partition, rearrange and regroup numbers to at least tens of thousands to assist calculations and solve problems. ACMNA083 Patterns and algebra • Use equivalent number sentences involving addition and subtraction to find unknown quantities.14
Work backwards, use a table
Fourchildrenbroughthomefishfordinner.Tamcaughtthesmallestfish,25cmshorterthanGrace’s.Grace’sfishwas10cmlongerthanTeddy’s.Teddy’sfishwas12cmlongerthanHarry’sfish,whichwas25cmlong.Howlongweretheotherfish?
HarryTeddyGraceTam
Harry’sfish=25cm
Teddy’sfish=25+12=_____________
Grace’sfish=__________________________
Tam’sfish=____________________________
Checkbackwards:22+25–________–________=________cm=Harry’sfish
1 ThetemperatureinDubboonWednesdaywas5degreeshigherthaninWellington.Wellingtonwas8degreescoolerthanParkes,whichwas2degreeshotterthanForbes.Forbes’temperaturewas34degrees,sowhattemperatureswerereportedattheothertowns?
Forbes=________________________________
Parkes=________________________________
Wellington=___________________________
Dubbo=________________________________
2 Inthemathstest,Deegainedabetterscorethanlastweek,butstill10lessthanKay.Kay’sscorewas5lessthanherfriend,Len.Lengained12morethanRod,whoscored85.Whosemarkwashighestandwhatweretheother’sscores?
______________________________________________________________________________________________________
______________________________________________________________________________________________________
______________________________________________________________________________________________________
3 Writeyourownproblemwiththisending.Pete’s house is 32 km from school. Who lives farthest from school?
______________________________________________________________________________________________________
______________________________________________________________________________________________________
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