+/- Numbers Year 2-3 – Develop methods for addition and subtraction within 100 www.KeyStage2Maths.com

34 = 30 + 4

34 = 20 + 14

34 = 10 + 24

76 = 70 + 6

76 = 60 + 16

76 = 50 + 26

76 = 40 + 36

76 = 30 + 46

76 = 20 + 56

76 = 10 + 66

82 = 80 + 2

82 = 70 + 12

82 = 60 + 22

82 = 50 + 32

82 = 40 + 42

82 = 30 + 52

82 = 20 + 62

82 = 10 + 72

Round 23 to the nearest 10 20 21 22 23 24 25 26 27 28 29 30 23 20

Round 28 to the nearest 10 20 21 22 23 24 25 26 27 28 29 30 28 30

Round 41 to the nearest 10 40 41 42 43 44 45 46 47 48 49 50 41 40

Round 66 to the nearest 10 70 69 68 67 66 65 64 63 62 61 60 66 70

Round 55 to the nearest 10 60 59 58 57 56 55 54 53 52 51 50 55 60

Round 25 to the nearest 10 30 29 28 27 26 25 24 23 22 21 20 25 30

When rounding to the nearest ten: If the units digit is 1, 2, 3 or 4, go BACK to the previous multiple of ten. If the units digit is 5, 6, 7, 8 or 9, go ON to the next multiple of ten.

+ 6 9 7 +2 +4 28 34 28 30 34 66 75

+ 6 9 7 +2 +7 28 34 37 28 30 37 66 75

+ 6 9 7 +2 +5 28 34 37 35 28 30 35 66 75

+ 6 9 7 +4 +2 28 34 37 35 66 70 72 66 72 75

+ 6 9 7 +4 +5 28 34 37 35 66 70 75 66 72 75 75

+ 6 9 7 +4 +3 28 34 37 35 66 70 73 66 72 75 73 75

+ 6 9 7 +5 +1 28 34 37 35 75 80 81 66 72 75 73 75 81

+ 6 9 7 +5 +4 28 34 37 35 75 80 84 66 72 75 73 75 81 84

+ 6 9 7 +5 +2 28 34 37 35 75 80 82 66 72 75 73 75 81 84 82

- 6 9 7 -1 -5 25 19 19 20 25 64 72

- 6 9 7 -4 -5 25 19 16 16 20 25 64 72

- 6 9 7 -2 -5 25 19 16 18 18 20 25 64 72

- 6 9 7 -2 -4 25 19 16 18 58 60 64 64 58 72

- 6 9 7 -5 -4 25 19 16 18 55 60 64 64 58 55 72

- 6 9 7 -3 -4 25 19 16 18 57 60 64 64 58 55 57 72

- 6 9 7 -4 -2 25 19 16 18 66 70 72 64 58 55 57 72 66

- 6 9 7 -7 -2 25 19 16 18 63 70 72 64 58 55 57 72 66 63

- 6 9 7 -5 -2 25 19 16 18 65 70 72 64 58 55 57 72 66 63 65

8 4 – 4 3 = 4 1 +7 +10 +10 +10 +4 43 50 60 70 80 84 10 + 10 + 10 + 7 + 4 = Adding by counting forwards on a number line 30 + 11 = 41

8 4 – 4 3 = 4 1 +7 +30 +4 43 50 80 84 30 + 7 + 4 = Adding by counting forwards on a number line 30 + 11 = 41

7 1 – 5 6 = 1 5 +4 +10 +1 56 70 71 60 10 + 4 + 1 = Adding by counting forwards on a number line 10 + 5 = 15

8 2 – 5 8 = 2 4 +2 +10 +10 +2 58 60 70 80 82 Adding by counting forwards on a number line 10 + 10 + 2 + 2 = 20 + 4 = 24

8 2 – 5 8 = 2 4 +2 +20 +2 58 60 80 82 Adding by counting forwards on a number line 20 + 2 + 2 = 20 + 4 = 24

7 0 – 3 8 = 3 2 +10 +10 +10 +2 38 40 50 60 70 Adding by counting forwards on a number line 10 + 10 + 10 + 2 = 30 + 2 = 32

7 0 – 3 8 = 3 2 +30 +2 38 40 70 Adding by counting forwards on a number line 30 + 2 = 32

8 4 – 4 3 = _ _ 4 1 +10 +10 +10 +10 +1 43 53 63 73 83 84 Adding by counting forwards on a number line

8 4 – 4 3 = _ _ 4 1 +40 +1 43 83 84 Adding by counting forwards on a number line

7 1 – 5 6 = _ _ 1 5 +10 +1 +1 +1 +1 +1 56 66 67 68 69 70 71 Adding by counting forwards on a number line

7 1 – 5 6 = _ _ 1 5 +10 +4 +1 56 66 70 71 Adding by counting forwards on a number line

8 2 – 5 8 = _ _ 2 4 +10 +10 +1 +1 +1 +1 58 68 78 79 80 81 82 Adding by counting forwards on a number line

8 2 – 5 8 = _ _ 2 4 +20 +2 +2 58 78 80 82 Adding by counting forwards on a number line

7 0 – 3 8 = _ _ 3 2 +10 +10 +10 +1 +1 38 48 58 68 69 70 Adding by counting forwards on a number line

7 0 – 3 8 = _ _ 3 2 +30 +2 38 68 70 Adding by counting forwards on a number line

4 3 + 9 = 52 Adding by counting forwards on a number line

5 9 + 9 = 68 Adding by counting forwards on a number line

6 + 9 = 15 Adding by counting forwards on a number line

4 7 - 9 = 38 Adding by counting forwards on a number line

7 5 - 9 = 66 Adding by counting forwards on a number line

6 1 - 9 = 52 Adding by counting forwards on a number line

4 3 + 9 = 52 +10 -1 43 52 53 Adding by counting forwards on a number line

5 9 + 9 = 68 +10 -1 59 68 69 Adding by counting forwards on a number line

6 + 9 = 15 +10 -1 6 15 16 Adding by counting forwards on a number line

4 7 - 9 = 38 +1 -10 37 38 47 Adding by counting forwards on a number line

7 5 - 9 = 66 +1 -10 65 66 75 Adding by counting forwards on a number line

6 1 - 9 = 52 +1 -10 51 52 61 Adding by counting forwards on a number line

5 4 + 8 = 62 Adding by counting forwards on a number line

2 7 + 8 = 35 Adding by counting forwards on a number line

8 8 + 8 = 96 Adding by counting forwards on a number line

6 3 - 8 = 55 Adding by counting forwards on a number line

1 5 - 8 = 7 Adding by counting forwards on a number line

4 6 - 8 = 38 Adding by counting forwards on a number line

5 4 + 8 = 62 +10 -2 54 62 64 Adding by counting forwards on a number line

2 7 + 8 = 35 +10 -2 27 35 37 Adding by counting forwards on a number line

8 8 + 8 = 96 +10 -2 88 96 98 Adding by counting forwards on a number line

6 3 - 8 = 55 +2 -10 53 55 63 Adding by counting forwards on a number line

1 5 - 8 = 7 +2 -10 5 7 15 Adding by counting forwards on a number line

4 6 - 8 = 38 +2 -10 36 38 46 Adding by counting forwards on a number line

33 + 29 = 62 Adding by counting forwards on a number line

55 + 39 = 94 Adding by counting forwards on a number line

22 + 19 = 41 Adding by counting forwards on a number line

57 - 19 = 38 Adding by counting forwards on a number line

70 - 29 = 41 Adding by counting forwards on a number line

81 - 49 = 32 Adding by counting forwards on a number line

33 + 29 = 62 +30 -1 33 62 63 Adding by counting forwards on a number line

55 + 39 = 94 +40 -1 55 94 95 Adding by counting forwards on a number line

22 + 19 = 41 +20 -1 22 41 42 Adding by counting forwards on a number line

57 - 19 = 38 +1 -20 37 38 57 Adding by counting forwards on a number line

70 - 29 = 41 +1 -30 40 41 70 Adding by counting forwards on a number line

81 - 49 = 32 +1 -50 31 32 81 Adding by counting forwards on a number line

64 + 28 = 92 Adding by counting forwards on a number line

27 + 18 = 45 Adding by counting forwards on a number line

69 + 28 = 97 Adding by counting forwards on a number line

77 - 28 = 49 Adding by counting forwards on a number line

83 - 48 = 35 Adding by counting forwards on a number line

44 - 18 = 26 Adding by counting forwards on a number line

64 + 28 = 92 +30 -2 64 92 94 Adding by counting forwards on a number line

27 + 18 = 45 +20 -2 27 45 47 Adding by counting forwards on a number line

69 + 28 = 97 +30 -2 69 97 99 Adding by counting forwards on a number line

77 - 28 = 49 +2 -30 47 49 77 Adding by counting forwards on a number line

83 - 48 = 35 +2 -50 33 35 83 Adding by counting forwards on a number line

44 - 18 = 26 +2 -20 24 26 44 Adding by counting forwards on a number line

16 7 9 3 4 5

27 12 15 5 7 8

27 13 14 8 5 9

27 12 15 5 7 8

2 + + = 4 3 9 Start with largest 4 + 3 = 7 7 + 2 = 9

+ + = 4 5 8 17 8 + 5 = 13 13 + 4 = 17 Start with largest Bridging 8 10 +2 +3 8 + 5 = 13 8 10 13 13 + 4 = 17

4 + + 1 6 + 7 = 18 Make ten 6 + 4 = 10 10 + 7 = 17 17 + 1 = 18

4 + + 7 6 + 3 = 20 Make ten 4 + 6 = 10 Make ten 7 + 3 = 10 10 + 10 = 20

5 + + 7 6 + 5 = 23 Make ten 5 + 5 = 10 10 + 7 = 17 Bridging +3 +3 17 + 6 = 23 17 20 23

2 + + 9 8 + 9 = 28 Make ten 2 + 8 = 10 10 + 9 = 19 +10 -1 Add 9 (10-1) 19 28 29 19 + 9 = 28

4 6 + _ _ = 100 5 4 54 + 46 = 100 100 100 – 54 = 46 46 54 100 – 46 = 54

4 6 + _ _ = 100 5 4 40 6 50 4 40 + 50 = 90 6 + 4 = 10 100

3 3 + _ _ = 100 6 7 67 + 33 = 100 100 100 – 67 = 33 33 67 100 – 33 = 67

3 3 + _ _ = 100 6 7 30 3 60 7 30 + 60 = 90 3 + 7 = 10 100

7 1 + _ _ = 100 9 2 70 1 70 + __ = 90 20 1 + _ = 10 9 100

7 1 + _ _ = 100 2 9 29 + 71 = 100 100 100 – 29 = 71 71 29 100 – 71 = 29

5 7 + _ _ = 100 3 4 50 7 50 + __ = 90 40 7 + _ = 10 3 100

8 5 + _ _ = 100 5 1 80 5 80 + __ = 90 10 5 + _ = 10 5 100

10 4 9 4 9 20 4 9 30 4 9 40 4 9 50 4 9 60 4 9 70 4 9

8 13 18 23 28 33 38 43 48 53 Complete +10 number sequences

90 1 80 6 1 70 6 1 60 6 1 50 6 1 40 6 1 30 6 1 20 6 1

93 88 83 78 73 68 63 58 53 48 Complete +10 number sequences