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

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

1.127 + 38 = 127 + 40 − (answer space) = (answer space)

Answer: 2, 165

  1. 127 + 40 = 167
  2. 167 − 2 = 165
2.66 − 28 = 66 − 30 + (answer space) = (answer space)

Answer: 2, 38

  1. 66 − 30 = 36
  2. I took away 2 too many, so add it back: 36 + 2 = 38
3.191 − 9 = 191 − 1 − (answer space) = (answer space)

Answer: 8, 182

  1. 191 − 1 = 190 (back to a ten)
  2. 190 − 8 = 182
4.171 + 28 = 171 + 30 − (answer space) = (answer space)

Answer: 2, 199

  1. 171 + 30 = 201
  2. 201 − 2 = 199
5.27 − 9 = 27 − 10 + (answer space) = (answer space)

Answer: 1, 18

  1. 27 − 10 = 17
  2. I took away 1 too many, so add it back: 17 + 1 = 18
6.111 − 8 = 111 − 1 − (answer space) = (answer space)

Answer: 7, 103

  1. 111 − 1 = 110 (back to a ten)
  2. 110 − 7 = 103
7.102 + 99 = 102 + 100 − (answer space) = (answer space)

Answer: 1, 201

  1. 102 + 100 = 202
  2. 202 − 1 = 201
8.120 − 28 = 120 − 30 + (answer space) = (answer space)

Answer: 2, 92

  1. 120 − 30 = 90
  2. I took away 2 too many, so add it back: 90 + 2 = 92
9.42 − 9 = 42 − 2 − (answer space) = (answer space)

Answer: 7, 33

  1. 42 − 2 = 40 (back to a ten)
  2. 40 − 7 = 33
10.73 + 28 = 73 + 30 − (answer space) = (answer space)

Answer: 2, 101

  1. 73 + 30 = 103
  2. 103 − 2 = 101
11.53 − 28 = 53 − 30 + (answer space) = (answer space)

Answer: 2, 25

  1. 53 − 30 = 23
  2. I took away 2 too many, so add it back: 23 + 2 = 25
12.154 − 6 = 154 − 4 − (answer space) = (answer space)

Answer: 2, 148

  1. 154 − 4 = 150 (back to a ten)
  2. 150 − 2 = 148
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