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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.

1.63 + 39 = 63 + 40 − (answer space) = (answer space)

Answer: 1, 102

  1. 63 + 40 = 103
  2. 103 − 1 = 102
2.137 − 59 = 137 − 60 + (answer space) = (answer space)

Answer: 1, 78

  1. 137 − 60 = 77
  2. I took away 1 too many, so add it back: 77 + 1 = 78
3.181 − 8 = 181 − 1 − (answer space) = (answer space)

Answer: 7, 173

  1. 181 − 1 = 180 (back to a ten)
  2. 180 − 7 = 173
4.34 + 98 = 34 + 100 − (answer space) = (answer space)

Answer: 2, 132

  1. 34 + 100 = 134
  2. 134 − 2 = 132
5.208 − 98 = 208 − 100 + (answer space) = (answer space)

Answer: 2, 110

  1. 208 − 100 = 108
  2. I took away 2 too many, so add it back: 108 + 2 = 110
6.173 − 8 = 173 − 3 − (answer space) = (answer space)

Answer: 5, 165

  1. 173 − 3 = 170 (back to a ten)
  2. 170 − 5 = 165
7.137 + 59 = 137 + 60 − (answer space) = (answer space)

Answer: 1, 196

  1. 137 + 60 = 197
  2. 197 − 1 = 196
8.80 − 18 = 80 − 20 + (answer space) = (answer space)

Answer: 2, 62

  1. 80 − 20 = 60
  2. I took away 2 too many, so add it back: 60 + 2 = 62
9.154 − 7 = 154 − 4 − (answer space) = (answer space)

Answer: 3, 147

  1. 154 − 4 = 150 (back to a ten)
  2. 150 − 3 = 147
10.127 + 18 = 127 + 20 − (answer space) = (answer space)

Answer: 2, 145

  1. 127 + 20 = 147
  2. 147 − 2 = 145
11.127 − 29 = 127 − 30 + (answer space) = (answer space)

Answer: 1, 98

  1. 127 − 30 = 97
  2. I took away 1 too many, so add it back: 97 + 1 = 98
12.82 − 3 = 82 − 2 − (answer space) = (answer space)

Answer: 1, 79

  1. 82 − 2 = 80 (back to a ten)
  2. 80 − 1 = 79
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