Year 7 Prime Factorisation (Factor Trees) Worksheet — Level 1 — 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 1 — 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 30 as a product of prime factors.
Answer: 2×3×5
- 30 = 2 × 15
- 15 = 3 × 5
- So 30 = 2 × 3 × 5
2.Use a factor tree to write 45 as a product of prime factors.
Answer: 3×3×5
- 45 = 3 × 15
- 15 = 3 × 5
- So 45 = 3 × 3 × 5 = 32 × 5
3.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
4.Use a factor tree to write 12 as a product of prime factors.
Answer: 2×2×3
- 12 = 2 × 6
- 6 = 2 × 3
- So 12 = 2 × 2 × 3 = 22 × 3
5.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
6.Use a factor tree to write 90 as a product of prime factors.
Answer: 2×3×3×5
- 90 = 2 × 45
- 45 = 3 × 15
- 15 = 3 × 5
- So 90 = 2 × 3 × 3 × 5 = 2 × 32 × 5
7.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
8.Use a factor tree to write 20 as a product of prime factors.
Answer: 2×2×5
- 20 = 2 × 10
- 10 = 2 × 5
- So 20 = 2 × 2 × 5 = 22 × 5
Marking tips
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