Year 3 Mental Addition and Subtraction Strategies Worksheet — Level 2 — Practice Set 3 — 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 3 — Answers
Fill in each step of the strategy, then write the answer.
1.75 + 6 = 75 + 5 + (answer space) = (answer space)
Answer: 1, 81
- 75 + 5 = 80 (a ten)
- 80 + 1 = 81
2.32 + 9 = 32 + 10 − (answer space) = (answer space)
Answer: 1, 41
- 32 + 10 = 42
- 42 − 1 = 41
3.11 + 12 = (answer space) + (answer space) + 1 = (answer space)
Answer: 11, 11, 23
- Double 11 is 22
- 22 + 1 = 23
4.49 + 4 = 49 + 1 + (answer space) = (answer space)
Answer: 3, 53
- 49 + 1 = 50 (a ten)
- 50 + 3 = 53
5.23 + 9 = 23 + 10 − (answer space) = (answer space)
Answer: 1, 32
- 23 + 10 = 33
- 33 − 1 = 32
6.11 + 10 = (answer space) + (answer space) + 1 = (answer space)
Answer: 10, 10, 21
- Double 10 is 20
- 20 + 1 = 21
7.78 + 7 = 78 + 2 + (answer space) = (answer space)
Answer: 5, 85
- 78 + 2 = 80 (a ten)
- 80 + 5 = 85
8.34 + 9 = 34 + 10 − (answer space) = (answer space)
Answer: 1, 43
- 34 + 10 = 44
- 44 − 1 = 43
9.44 + 43 = (answer space) + (answer space) + 1 = (answer space)
Answer: 43, 43, 87
- Double 43 is 86
- 86 + 1 = 87
10.47 + 5 = 47 + 3 + (answer space) = (answer space)
Answer: 2, 52
- 47 + 3 = 50 (a ten)
- 50 + 2 = 52
11.33 + 9 = 33 + 10 − (answer space) = (answer space)
Answer: 1, 42
- 33 + 10 = 43
- 43 − 1 = 42
12.81 + 80 = (answer space) + (answer space) + 1 = (answer space)
Answer: 80, 80, 161
- Double 80 is 160
- 160 + 1 = 161
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.