Year 7 Prime Factorisation (Factor Trees) Worksheet — Level 2 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 7 factors, multiples & primes worksheet.
Success TutoringWorksheetsAnswer sheetYear 7 · Mathematics · Factors, Multiples & PrimesYear 7 Prime Factorisation (Factor Trees) Worksheet — Level 2 — Practice Set 4 — Answers
Keep splitting each number into two factors until every branch ends in a prime. Write the primes from smallest to largest.
1.Use a factor tree to write 50 as a product of prime factors.
Answer: 2×5×5
- 50 = 2 × 25
- 25 = 5 × 5
- So 50 = 2 × 5 × 5 = 2 × 52
2.Use a factor tree to write 84 as a product of prime factors.
Answer: 2×2×3×7
- 84 = 2 × 42
- 42 = 2 × 21
- 21 = 3 × 7
- So 84 = 2 × 2 × 3 × 7 = 22 × 3 × 7
3.Use a factor tree to write 60 as a product of prime factors.
Answer: 2×2×3×5
- 60 = 2 × 30
- 30 = 2 × 15
- 15 = 3 × 5
- So 60 = 2 × 2 × 3 × 5 = 22 × 3 × 5
4.Which number has the prime factorisation 2 × 32 × 7?
Answer: 126
- 2 × 3 × 3 × 7 = 126
5.Use a factor tree to write 294 as a product of prime factors.
Answer: 2×3×7×7
- 294 = 2 × 147
- 147 = 3 × 49
- 49 = 7 × 7
- So 294 = 2 × 3 × 7 × 7 = 2 × 3 × 72
6.Use a factor tree to write 98 as a product of prime factors.
Answer: 2×7×7
- 98 = 2 × 49
- 49 = 7 × 7
- So 98 = 2 × 7 × 7 = 2 × 72
7.Use a factor tree to write 196 as a product of prime factors.
Answer: 2×2×7×7
- 196 = 2 × 98
- 98 = 2 × 49
- 49 = 7 × 7
- So 196 = 2 × 2 × 7 × 7 = 22 × 72
8.Which number has the prime factorisation 2 × 3 × 7?
Answer: 42
- 2 × 3 × 7 = 42
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.