Mental MathsGrade 3 Workbook

ANN GROENEWALD l ZELDA PENNY

4

AAdddd aanndd ssuubbttrraacctt mmuullttiipplleess ooff tteenn20 + 30 = 90 - 80 =40 + 50 = 80 - 60 =70 + 20 = 50 - 10 =10 + 20 + 30 = 90 - 20 - 10 =40 + 40 + 20 = 70 - 40 - 30 =70 + 10 + 0 = 100 - 50 - 10 =10 + 50 + 30 = 70 - 60 - 10 =

CCoouunntt iinn tteennss

CCoouunntt iinn ttwweennttiieess

CCoouunntt iinn tteennss

CCoommpplleettee1 more than 30 is 10 more than 20 is 2 less than 50 is 20 less than 70 is 3 more than 80 is 30 more than 40 is 4 less than 60 is 40 less than 90 is

10 20 90130

20 200

15 105

30 70

50

10

60

80

20

70

90

40

0

100 100

5

CCoouunnttiinngg ffoorrwwaarrddss oorr bbaacckkwwaarrddss ttoo ssoollvvee pprroobblleemmss

7 + 6 = 11 - 4 = 14 - 5 =8 + 5 = 13 - 5 = 5 + 5 =9 + 4 = 19 - 3 = 8 + 3 =6 + 6 = 20 - 6 = 13 + 4 =5 + 4 = 12 - 5 = 6 + 4 =10 + 5 = 9 - 2 = 15 - 5 =18 + 3 = 17 - 4 = 10 + 6=11 + 4 = 12 - 3 = 16 + 3 =13 + 5 = 15 - 3 = 17 - 3 =12 + 8 = 14 - 6 = 14 + 4=8 + 6 = 11 - 2 = 13 - 4 =

6

CCoouunntt ffoorrwwaarrddss oorr bbaacckkwwaarrddss oonn tthhee nnuummbbeerr lliinnee ttoo ssoollvvee tthhee pprroobblleemmss

15 - 7

9 + 6

14 - 6

8 + 7

13 - 6

7 + 6

RReeppeeaatteedd aaddddiittiioonn // MMuullttiipplliiccaattiioonn

5+5+5+5+5+5= 5x6=

5+5+5= 5x3=

5+5+5+5+5= 5x5=

5+5+5+5+5+5+5+5= 5x8=

5+5+5+5+5+5+5= 5x7=

5+5+5+5= 5x4=

0

0

0

0

0

0

10 -7

10

10

10

10

10

20

20

20

20

20

20

ll

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IIIIIIIIIIIIIII

IIII

IIIIIIII

15

7

MMeennttaall ccaallccuullaattiioonnss

MMaaggiicc ssqquuaarreessThe sum of the numbers in each row across, down anddiagonally must equal the number in the star.

NNuummbbeerr nnaammeess BBuuiilldd tthhee nnuummbbeerrss12 12 = +15 15 = +18 18 = +34 34 = +27 27 = +45 45 = +

9

-5108711

12

-47

810

9

9 12 15

5

0 7 1

5

5 8

24

2 2

37

NNeeaarr--zzeerroo aannsswweerrss26 - 25 = 24 - 23 =25 - 24 = 20 - 19 =28 - 27 = 21 - 19 =26 - 24 = 22 - 21 =23 - 22 = 30 - 29 =

AAdddd aanndd ssuubbttrraacctt mmuullttiipplleess ooff tteennss//hhuunnddrreeddss1 + 2 = 10 + 20 = 100 + 200 =6 + 3 = 60 + 30 = 600 + 300 =4 - 2 = 40 - 20 = 400 - 200 =7 - 3 = 70 - 30 = 700 - 300 =3 + 5 = 30 + 50 = 300 + 500 =9 - 7 = 90 - 70 = 900 - 700 =

TTaabblleess4 x 1 =2 x 8 =4 x 5 =2 x 9 =4 x 3 =2 x 6 =4 x 10 =

4 x 0 =2 x 1 =4 x 2 =2 x 10 =4 x 6 =2 x 5 =2 x 0 =

4 x 8 =2 x 2 =4 x 4 =2 x 3 = 4 x 7 =2 x 4 = 4 x 9 =

7 7 7

38

RReeppeeaatteedd ssuubbttrraaccttiioonn ttoo ssoollvvee ddiivviissiioonn pprroobblleemmss

14 ÷ 2

16 ÷ 2

16 ÷ 4

20 ÷ 2

18 ÷ 2

20 ÷ 4

12 ÷ 4

12 ÷ 2

0 10

-2 -2 -2 -2 -2 -2 -2

20

0 10 20

0 10 20

0 10 20

0 10 20

0 10 20

0 10 20

0 10 20

take away 2repeatedly untilyou get to 0

14

57

CCoouunntt ffoorrwwaarrddss CCoouunntt bbaacckkwwaarrddss

369 500394 464421 372465 305298 217

CCoommpplleetteeNumber name hundreds tens ones

eighty nine 8 9one hundred and seventy twotwo hundred and twoninety threethree hundred and sixteen

+5 9 15 28 13 27 34 16 22 31 10 19

-6 9 15 13 28 37 14 36 12 11 21 43

x5 9 5 8 3 7 4 6 2 1 10 11

58

BBrreeaakk uupp aanndd bbuuiilldd nnuummbbeerrss ttoo aadddd aanndd ssuubbttrraacctt17 + 12 = 34 - 22 = 17 + 18 =23 + 15 = 29 - 15 = 25 + 17 =32 + 18 = 35 - 24 = 36 - 19 =18 + 21 = 40 - 15 = 24 - 15 =114 + 11 = 126 - 15 = 125 - 16 =225 + 13 = 240 - 17 = 215 + 18 =305 + 15 = 419 - 9 = 324 - 15 =

TTaabblleess xx 88

8 + 8 = 8 x 2 =8 + 8 + 8 + 8 + 8 + 8 + 8 = 8 x 7 =8 + 8 + 8 + 8 = 8 x 4 =8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 = 8 x 9 =8 + 8 + 8 = 8 x 3 =8 + 8 + 8 + 8 + 8 = 8 x 5 =8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 = 8 x 8 =8 + 8 + 8 + 8 + 8 + 8 = 8 x 6 =

CCoommpplleettee

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4 x 1 =4 x 2 =8 x 1 =8 x 2 =8 x 3 =

4 x 1 =4 x 4 =4 x 6 =8 x 3 =8 x 6 =

4 x 5 =4 x 6 =8 x 3 =8 x 6 =8 x 7 =

4 x 7 =4 x 8 =8 x 4 =8 x 8 =8 x 9 =

4 x 9 =4 x 10 =8 x 5 =8 x 10 =8 x 11 =

82

CCoouunntt iinn oonneess

CCoommpplleettee

AAddddiittiioonn

671 672 680685

699708

Number name hundreds tens ones

six hundred and ninety onefive hundred and seventeenfour hundred and sixty twothree hundred and fourteentwo hundred and eight

round off tonearest 10

1144 77

22

11

11

22

33

553322

33

22

22

2200

11

99

0022 33

33

11

88

77

22

55112266

11

771166

881155

77 1144 1133 551122

44

331188

1111111100

55

1177

2277

83

FFiillll iinn tthhee mmiissssiinngg nnuummbbeerrss

What must I add to 1 to get 5 ?What must I add to 11 to get 15?What must I add to 21 to get 25?What must I add to 31 to get 35?What must I subtract from 7 to get 5?What must I subtract from 17 to get 15?What must I subtract from 27 to get 25?What must I subtract from 37 to get 35?

CCoouunntt ffoorrwwaarrddss oorr bbaacckkwwaarrddss ttoo ssoollvvee pprroobblleemmss..38 - 6 = 32 - 8 = 37 + 6 =27 + 9 = 35 + 7 = 25 - 8 =31 - 6 = 40 - 6 = 28 + 7 =43 - 7 = 46 - 7 = 33 - 5 =47 - 8 = 48 + 8 = 36 + 9 =39 + 5 = 30 - 6 = 41 - 7 =34 - 8 = 24 + 9 = 44 - 8 =45 - 6 = 42 - 5 = 29 + 7 =

650 656

650 656

650 656

84

CCoouunntt oonn iinn ssmmaallll nnuummbbeerrss ttoo ssoollvvee ssuubbttrraaccttiioonn pprroobblleemmss..

CCoommpplleettee

47 - 16 =42 - 15 =50 - 19 =36 - 15 =31 - 19 =44 - 14 =43 - 18 =40 - 13 =34 - 17 =41 - 12 =

48 - 20 =39 - 15 =49 - 13 =46 - 35 =50 - 18 =45 - 39 =42 - 20 =37 - 16 =33 - 17 =47 - 12 =

35 - 14 =45 - 19 =48 - 18 =46 - 14 =49 - 17 =41 - 16 =38 - 13 =32 - 20 =43 - 37 =50 - 25 =

+4 -5 +3 -2 x2 ÷2 +9 -6 x3 x105 9 08679

10 10 10

85

MMuullttiipplliiccaattiioonn ooff 22 ddiiggiittss wwiitthh 11 ddiiggiitt.. TTaabblleess

12 x 7 =10 x 7 =2 x 7 =

12 x 7 =

11 x 7 =

13 x 7 = 17 x 7 =

15 x 7 = 19 x 7 =

14 x 7 = 18 x 7 =

1 x 7 =2 x 9 =3 x 1 =4 x 8 =5 x 5 =6 x 7 =7 x 9 =8 x 1 =9 x 3 =10 x 5 =0 x 4 =1 x 8 =2 x 10 =3 x 2 =4 x 9 =5 x 6 =6 x 8 =7 x 10 =8 x 2 =9 x 4 =10 x 10 =3 x 0 =