Year 5 Prime Factorisation (Factor Trees) Worksheet — Level 2 — Answers
Answer sheet with worked solutions for the Year 5 factors, multiples & primes worksheet.
Success TutoringWorksheetsAnswer sheetYear 5 · Mathematics · Factors, Multiples & PrimesYear 5 Prime Factorisation (Factor Trees) Worksheet — Level 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 147 as a product of prime factors.
Answer: 3×7×7
- 147 = 3 × 49
- 49 = 7 × 7
- So 147 = 3 × 7 × 7 = 3 × 72
2.Use a factor tree to write 70 as a product of prime factors.
Answer: 2×5×7
- 70 = 2 × 35
- 35 = 5 × 7
- So 70 = 2 × 5 × 7
3.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
4.Which number has the prime factorisation 2 × 3 × 52?
Answer: 150
- 2 × 3 × 5 × 5 = 150
5.Use a factor tree to write 100 as a product of prime factors.
Answer: 2×2×5×5
- 100 = 2 × 50
- 50 = 2 × 25
- 25 = 5 × 5
- So 100 = 2 × 2 × 5 × 5 = 22 × 52
6.Use a factor tree to write 75 as a product of prime factors.
Answer: 3×5×5
- 75 = 3 × 25
- 25 = 5 × 5
- So 75 = 3 × 5 × 5 = 3 × 52
7.Use a factor tree to write 42 as a product of prime factors.
Answer: 2×3×7
- 42 = 2 × 21
- 21 = 3 × 7
- So 42 = 2 × 3 × 7
8.Which number has the prime factorisation 2 × 3 × 5?
Answer: 30
- 2 × 3 × 5 = 30
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.