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3rd Grade Mental Addition and Subtraction Strategies Worksheet — Level 3 — Practice Set 2 — Answers

Answer sheet with worked solutions for the 3rd Grade addition worksheet.

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Success TutoringWorksheetsAnswer sheet3rd Grade · Mathematics · Addition

3rd Grade Mental Addition and Subtraction Strategies Worksheet — Level 3 — Practice Set 2 — Answers

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

1.161 + 9 = 161 + 10 − (answer space) = (answer space)

Answer: 1, 170

  1. 161 + 10 = 171
  2. 171 − 1 = 170
2.86 − 39 = 86 − 40 + (answer space) = (answer space)

Answer: 1, 47

  1. 86 − 40 = 46
  2. I took away 1 too many, so add it back: 46 + 1 = 47
3.74 − 6 = 74 − 4 − (answer space) = (answer space)

Answer: 2, 68

  1. 74 − 4 = 70 (back to a ten)
  2. 70 − 2 = 68
4.84 + 18 = 84 + 20 − (answer space) = (answer space)

Answer: 2, 102

  1. 84 + 20 = 104
  2. 104 − 2 = 102
5.58 − 18 = 58 − 20 + (answer space) = (answer space)

Answer: 2, 40

  1. 58 − 20 = 38
  2. I took away 2 too many, so add it back: 38 + 2 = 40
6.121 − 7 = 121 − 1 − (answer space) = (answer space)

Answer: 6, 114

  1. 121 − 1 = 120 (back to a ten)
  2. 120 − 6 = 114
7.156 + 38 = 156 + 40 − (answer space) = (answer space)

Answer: 2, 194

  1. 156 + 40 = 196
  2. 196 − 2 = 194
8.142 − 38 = 142 − 40 + (answer space) = (answer space)

Answer: 2, 104

  1. 142 − 40 = 102
  2. I took away 2 too many, so add it back: 102 + 2 = 104
9.112 − 6 = 112 − 2 − (answer space) = (answer space)

Answer: 4, 106

  1. 112 − 2 = 110 (back to a ten)
  2. 110 − 4 = 106
10.175 + 18 = 175 + 20 − (answer space) = (answer space)

Answer: 2, 193

  1. 175 + 20 = 195
  2. 195 − 2 = 193
11.50 − 39 = 50 − 40 + (answer space) = (answer space)

Answer: 1, 11

  1. 50 − 40 = 10
  2. I took away 1 too many, so add it back: 10 + 1 = 11
12.191 − 9 = 191 − 1 − (answer space) = (answer space)

Answer: 8, 182

  1. 191 − 1 = 190 (back to a ten)
  2. 190 − 8 = 182
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