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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.

1.84 + 19 = 84 + 20 − (answer space) = (answer space)

Answer: 1, 103

  1. 84 + 20 = 104
  2. 104 − 1 = 103
2.131 − 28 = 131 − 30 + (answer space) = (answer space)

Answer: 2, 103

  1. 131 − 30 = 101
  2. I took away 2 too many, so add it back: 101 + 2 = 103
3.74 − 9 = 74 − 4 − (answer space) = (answer space)

Answer: 5, 65

  1. 74 − 4 = 70 (back to a ten)
  2. 70 − 5 = 65
4.32 + 38 = 32 + 40 − (answer space) = (answer space)

Answer: 2, 70

  1. 32 + 40 = 72
  2. 72 − 2 = 70
5.72 − 18 = 72 − 20 + (answer space) = (answer space)

Answer: 2, 54

  1. 72 − 20 = 52
  2. I took away 2 too many, so add it back: 52 + 2 = 54
6.141 − 2 = 141 − 1 − (answer space) = (answer space)

Answer: 1, 139

  1. 141 − 1 = 140 (back to a ten)
  2. 140 − 1 = 139
7.186 + 98 = 186 + 100 − (answer space) = (answer space)

Answer: 2, 284

  1. 186 + 100 = 286
  2. 286 − 2 = 284
8.66 − 39 = 66 − 40 + (answer space) = (answer space)

Answer: 1, 27

  1. 66 − 40 = 26
  2. I took away 1 too many, so add it back: 26 + 1 = 27
9.131 − 8 = 131 − 1 − (answer space) = (answer space)

Answer: 7, 123

  1. 131 − 1 = 130 (back to a ten)
  2. 130 − 7 = 123
10.63 + 9 = 63 + 10 − (answer space) = (answer space)

Answer: 1, 72

  1. 63 + 10 = 73
  2. 73 − 1 = 72
11.178 − 98 = 178 − 100 + (answer space) = (answer space)

Answer: 2, 80

  1. 178 − 100 = 78
  2. I took away 2 too many, so add it back: 78 + 2 = 80
12.93 − 5 = 93 − 3 − (answer space) = (answer space)

Answer: 2, 88

  1. 93 − 3 = 90 (back to a ten)
  2. 90 − 2 = 88
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