Year 7 Prime Factorisation (Factor Trees) Worksheet — Level 2 — Practice Set 2 — 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 2 — 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 48 as a product of prime factors.
Answer: 2×2×2×2×3
- 48 = 2 × 24
- 24 = 2 × 12
- 12 = 2 × 6
- 6 = 2 × 3
- So 48 = 2 × 2 × 2 × 2 × 3 = 24 × 3
2.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
3.Use a factor tree to write 30 as a product of prime factors.
Answer: 2×3×5
- 30 = 2 × 15
- 15 = 3 × 5
- So 30 = 2 × 3 × 5
4.Which number has the prime factorisation 3 × 72?
Answer: 147
- 3 × 7 × 7 = 147
5.Use a factor tree to write 245 as a product of prime factors.
Answer: 5×7×7
- 245 = 5 × 49
- 49 = 7 × 7
- So 245 = 5 × 7 × 7 = 5 × 72
6.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
7.Use a factor tree to write 175 as a product of prime factors.
Answer: 5×5×7
- 175 = 5 × 35
- 35 = 5 × 7
- So 175 = 5 × 5 × 7 = 52 × 7
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.