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.
1.18 + 6 = 18 + 2 + (answer space) = (answer space)
Answer: 4, 24
- 18 + 2 = 20 (a ten)
- 20 + 4 = 24
2.35 + 9 = 35 + 10 − (answer space) = (answer space)
Answer: 1, 44
- 35 + 10 = 45
- 45 − 1 = 44
3.39 + 40 = (answer space) + (answer space) + 1 = (answer space)
Answer: 39, 39, 79
- Double 39 is 78
- 78 + 1 = 79
4.87 + 7 = 87 + 3 + (answer space) = (answer space)
Answer: 4, 94
- 87 + 3 = 90 (a ten)
- 90 + 4 = 94
5.63 + 9 = 63 + 10 − (answer space) = (answer space)
Answer: 1, 72
- 63 + 10 = 73
- 73 − 1 = 72
6.51 + 50 = (answer space) + (answer space) + 1 = (answer space)
Answer: 50, 50, 101
- Double 50 is 100
- 100 + 1 = 101
7.57 + 8 = 57 + 3 + (answer space) = (answer space)
Answer: 5, 65
- 57 + 3 = 60 (a ten)
- 60 + 5 = 65
8.27 + 9 = 27 + 10 − (answer space) = (answer space)
Answer: 1, 36
- 27 + 10 = 37
- 37 − 1 = 36
9.42 + 43 = (answer space) + (answer space) + 1 = (answer space)
Answer: 42, 42, 85
- Double 42 is 84
- 84 + 1 = 85
10.69 + 5 = 69 + 1 + (answer space) = (answer space)
Answer: 4, 74
- 69 + 1 = 70 (a ten)
- 70 + 4 = 74
11.33 + 9 = 33 + 10 − (answer space) = (answer space)
Answer: 1, 42
- 33 + 10 = 43
- 43 − 1 = 42
12.20 + 21 = (answer space) + (answer space) + 1 = (answer space)
Answer: 20, 20, 41
- Double 20 is 40
- 40 + 1 = 41
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.