Year 3 Mental Addition and Subtraction Strategies Worksheet — Level 2 — Practice Set 2 — Answers
Answer sheet with worked solutions for the Year 3 addition worksheet.
Success TutoringWorksheetsAnswer sheetYear 3 · Mathematics · AdditionYear 3 Mental Addition and Subtraction Strategies Worksheet — Level 2 — Practice Set 2 — Answers
Fill in each step of the strategy, then write the answer.
1.17 + 8 = 17 + 3 + (answer space) = (answer space)
Answer: 5, 25
- 17 + 3 = 20 (a ten)
- 20 + 5 = 25
2.58 + 9 = 58 + 10 − (answer space) = (answer space)
Answer: 1, 67
- 58 + 10 = 68
- 68 − 1 = 67
3.29 + 28 = (answer space) + (answer space) + 1 = (answer space)
Answer: 28, 28, 57
- Double 28 is 56
- 56 + 1 = 57
4.86 + 5 = 86 + 4 + (answer space) = (answer space)
Answer: 1, 91
- 86 + 4 = 90 (a ten)
- 90 + 1 = 91
5.32 + 9 = 32 + 10 − (answer space) = (answer space)
Answer: 1, 41
- 32 + 10 = 42
- 42 − 1 = 41
6.21 + 20 = (answer space) + (answer space) + 1 = (answer space)
Answer: 20, 20, 41
- Double 20 is 40
- 40 + 1 = 41
7.85 + 8 = 85 + 5 + (answer space) = (answer space)
Answer: 3, 93
- 85 + 5 = 90 (a ten)
- 90 + 3 = 93
8.52 + 9 = 52 + 10 − (answer space) = (answer space)
Answer: 1, 61
- 52 + 10 = 62
- 62 − 1 = 61
9.43 + 44 = (answer space) + (answer space) + 1 = (answer space)
Answer: 43, 43, 87
- Double 43 is 86
- 86 + 1 = 87
10.66 + 5 = 66 + 4 + (answer space) = (answer space)
Answer: 1, 71
- 66 + 4 = 70 (a ten)
- 70 + 1 = 71
11.11 + 9 = 11 + 10 − (answer space) = (answer space)
Answer: 1, 20
- 11 + 10 = 21
- 21 − 1 = 20
12.44 + 45 = (answer space) + (answer space) + 1 = (answer space)
Answer: 44, 44, 89
- Double 44 is 88
- 88 + 1 = 89
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.