Year 8 Prime Factorisation (Factor Trees) Worksheet — Level 2 — Answers
Answer sheet with worked solutions for the Year 8 factors, multiples & primes worksheet.
Success TutoringWorksheetsAnswer sheetYear 8 · Mathematics · Factors, Multiples & PrimesYear 8 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 45 as a product of prime factors.
Answer: 3×3×5
- 45 = 3 × 15
- 15 = 3 × 5
- So 45 = 3 × 3 × 5 = 32 × 5
2.Use a factor tree to write 126 as a product of prime factors.
Answer: 2×3×3×7
- 126 = 2 × 63
- 63 = 3 × 21
- 21 = 3 × 7
- So 126 = 2 × 3 × 3 × 7 = 2 × 32 × 7
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 2 × 72?
Answer: 98
- 2 × 7 × 7 = 98
5.Use a factor tree to write 210 as a product of prime factors.
Answer: 2×3×5×7
- 210 = 2 × 105
- 105 = 3 × 35
- 35 = 5 × 7
- So 210 = 2 × 3 × 5 × 7
6.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
7.Use a factor tree to write 63 as a product of prime factors.
Answer: 3×3×7
- 63 = 3 × 21
- 21 = 3 × 7
- So 63 = 3 × 3 × 7 = 32 × 7
8.Which number has the prime factorisation 32 × 5?
Answer: 45
- 3 × 3 × 5 = 45
Marking tips
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