Year 6 Prime Factorisation (Factor Trees) Worksheet — Level 3 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 6 factors, multiples & primes worksheet.
Success TutoringWorksheetsAnswer sheetYear 6 · Mathematics · Factors, Multiples & PrimesYear 6 Prime Factorisation (Factor Trees) Worksheet — Level 3 — Practice Set 4 — Answers
Keep splitting each number into two factors until every branch ends in a prime. Write repeated factors with an index, e.g. 2 × 2 × 2 = 23.
1.Use a factor tree to write 484 as a product of prime factors in index form.
Answer: 22×112
- 484 = 2 × 242
- 242 = 2 × 121
- 121 = 11 × 11
- So 484 = 2 × 2 × 11 × 11 = 22 × 112
2.Which number has the prime factorisation 2 × 5 × 72?
Answer: 490
- 2 × 5 × 7 × 7 = 490
3.Use a factor tree to write 990 as a product of prime factors in index form.
Answer: 2×32×5×11
- 990 = 2 × 495
- 495 = 3 × 165
- 165 = 3 × 55
- 55 = 5 × 11
- So 990 = 2 × 3 × 3 × 5 × 11 = 2 × 32 × 5 × 11
4.Which number has the prime factorisation 2 × 7 × 11?
Answer: 154
- 2 × 7 × 11 = 154
5.Use a factor tree to write 245 as a product of prime factors in index form.
Answer: 5×72
- 245 = 5 × 49
- 49 = 7 × 7
- So 245 = 5 × 7 × 7 = 5 × 72
6.Which number has the prime factorisation 22 × 3 × 7 × 11?
Answer: 924
- 2 × 2 × 3 × 7 × 11 = 924
7.Use a factor tree to write 70 as a product of prime factors in index form.
Answer: 2×5×7
- 70 = 2 × 35
- 35 = 5 × 7
- So 70 = 2 × 5 × 7 = 2 × 5 × 7
8.Which number has the prime factorisation 32 × 5 × 11?
Answer: 495
- 3 × 3 × 5 × 11 = 495
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.