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Year 4 Mental Addition and Subtraction Strategies Worksheet — Level 3 — Answers

Answer sheet with worked solutions for the Year 4 addition worksheet.

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Success TutoringWorksheetsAnswer sheetYear 4 · Mathematics · Addition

Year 4 Mental Addition and Subtraction Strategies Worksheet — Level 3 — Answers

Fill in each step of the strategy, then write the answer.

1.49 + 9 = 49 + 10 − (answer space) = (answer space)

Answer: 1, 58

  1. 49 + 10 = 59
  2. 59 − 1 = 58
2.142 − 39 = 142 − 40 + (answer space) = (answer space)

Answer: 1, 103

  1. 142 − 40 = 102
  2. I took away 1 too many, so add it back: 102 + 1 = 103
3.21 − 7 = 21 − 1 − (answer space) = (answer space)

Answer: 6, 14

  1. 21 − 1 = 20 (back to a ten)
  2. 20 − 6 = 14
4.77 + 18 = 77 + 20 − (answer space) = (answer space)

Answer: 2, 95

  1. 77 + 20 = 97
  2. 97 − 2 = 95
5.95 − 59 = 95 − 60 + (answer space) = (answer space)

Answer: 1, 36

  1. 95 − 60 = 35
  2. I took away 1 too many, so add it back: 35 + 1 = 36
6.124 − 9 = 124 − 4 − (answer space) = (answer space)

Answer: 5, 115

  1. 124 − 4 = 120 (back to a ten)
  2. 120 − 5 = 115
7.40 + 9 = 40 + 10 − (answer space) = (answer space)

Answer: 1, 49

  1. 40 + 10 = 50
  2. 50 − 1 = 49
8.156 − 48 = 156 − 50 + (answer space) = (answer space)

Answer: 2, 108

  1. 156 − 50 = 106
  2. I took away 2 too many, so add it back: 106 + 2 = 108
9.121 − 7 = 121 − 1 − (answer space) = (answer space)

Answer: 6, 114

  1. 121 − 1 = 120 (back to a ten)
  2. 120 − 6 = 114
10.40 + 39 = 40 + 40 − (answer space) = (answer space)

Answer: 1, 79

  1. 40 + 40 = 80
  2. 80 − 1 = 79
11.113 − 59 = 113 − 60 + (answer space) = (answer space)

Answer: 1, 54

  1. 113 − 60 = 53
  2. I took away 1 too many, so add it back: 53 + 1 = 54
12.183 − 6 = 183 − 3 − (answer space) = (answer space)

Answer: 3, 177

  1. 183 − 3 = 180 (back to a ten)
  2. 180 − 3 = 177
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