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

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

1.105 + 18 = 105 + 20 − (answer space) = (answer space)

Answer: 2, 123

  1. 105 + 20 = 125
  2. 125 − 2 = 123
2.177 − 59 = 177 − 60 + (answer space) = (answer space)

Answer: 1, 118

  1. 177 − 60 = 117
  2. I took away 1 too many, so add it back: 117 + 1 = 118
3.121 − 3 = 121 − 1 − (answer space) = (answer space)

Answer: 2, 118

  1. 121 − 1 = 120 (back to a ten)
  2. 120 − 2 = 118
4.103 + 48 = 103 + 50 − (answer space) = (answer space)

Answer: 2, 151

  1. 103 + 50 = 153
  2. 153 − 2 = 151
5.167 − 49 = 167 − 50 + (answer space) = (answer space)

Answer: 1, 118

  1. 167 − 50 = 117
  2. I took away 1 too many, so add it back: 117 + 1 = 118
6.192 − 4 = 192 − 2 − (answer space) = (answer space)

Answer: 2, 188

  1. 192 − 2 = 190 (back to a ten)
  2. 190 − 2 = 188
7.147 + 49 = 147 + 50 − (answer space) = (answer space)

Answer: 1, 196

  1. 147 + 50 = 197
  2. 197 − 1 = 196
8.74 − 48 = 74 − 50 + (answer space) = (answer space)

Answer: 2, 26

  1. 74 − 50 = 24
  2. I took away 2 too many, so add it back: 24 + 2 = 26
9.142 − 6 = 142 − 2 − (answer space) = (answer space)

Answer: 4, 136

  1. 142 − 2 = 140 (back to a ten)
  2. 140 − 4 = 136
10.140 + 98 = 140 + 100 − (answer space) = (answer space)

Answer: 2, 238

  1. 140 + 100 = 240
  2. 240 − 2 = 238
11.97 − 19 = 97 − 20 + (answer space) = (answer space)

Answer: 1, 78

  1. 97 − 20 = 77
  2. I took away 1 too many, so add it back: 77 + 1 = 78
12.34 − 6 = 34 − 4 − (answer space) = (answer space)

Answer: 2, 28

  1. 34 − 4 = 30 (back to a ten)
  2. 30 − 2 = 28
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