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

Answer sheet with worked solutions for the Year 3 addition worksheet.

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Success TutoringWorksheetsAnswer sheetYear 3 · Mathematics · Addition

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

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

1.166 + 39 = 166 + 40 − (answer space) = (answer space)

Answer: 1, 205

  1. 166 + 40 = 206
  2. 206 − 1 = 205
2.107 − 29 = 107 − 30 + (answer space) = (answer space)

Answer: 1, 78

  1. 107 − 30 = 77
  2. I took away 1 too many, so add it back: 77 + 1 = 78
3.134 − 6 = 134 − 4 − (answer space) = (answer space)

Answer: 2, 128

  1. 134 − 4 = 130 (back to a ten)
  2. 130 − 2 = 128
4.145 + 39 = 145 + 40 − (answer space) = (answer space)

Answer: 1, 184

  1. 145 + 40 = 185
  2. 185 − 1 = 184
5.82 − 19 = 82 − 20 + (answer space) = (answer space)

Answer: 1, 63

  1. 82 − 20 = 62
  2. I took away 1 too many, so add it back: 62 + 1 = 63
6.64 − 7 = 64 − 4 − (answer space) = (answer space)

Answer: 3, 57

  1. 64 − 4 = 60 (back to a ten)
  2. 60 − 3 = 57
7.50 + 98 = 50 + 100 − (answer space) = (answer space)

Answer: 2, 148

  1. 50 + 100 = 150
  2. 150 − 2 = 148
8.99 − 19 = 99 − 20 + (answer space) = (answer space)

Answer: 1, 80

  1. 99 − 20 = 79
  2. I took away 1 too many, so add it back: 79 + 1 = 80
9.22 − 4 = 22 − 2 − (answer space) = (answer space)

Answer: 2, 18

  1. 22 − 2 = 20 (back to a ten)
  2. 20 − 2 = 18
10.53 + 38 = 53 + 40 − (answer space) = (answer space)

Answer: 2, 91

  1. 53 + 40 = 93
  2. 93 − 2 = 91
11.82 − 49 = 82 − 50 + (answer space) = (answer space)

Answer: 1, 33

  1. 82 − 50 = 32
  2. I took away 1 too many, so add it back: 32 + 1 = 33
12.52 − 5 = 52 − 2 − (answer space) = (answer space)

Answer: 3, 47

  1. 52 − 2 = 50 (back to a ten)
  2. 50 − 3 = 47
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