Year 6 Prime Factorisation (Factor Trees) Worksheet — Level 2 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 6 factors, multiples & primes worksheet.
Success TutoringWorksheetsAnswer sheetYear 6 · Mathematics · Factors, Multiples & PrimesYear 6 Prime Factorisation (Factor Trees) Worksheet — Level 2 — Practice Set 3 — 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 105 as a product of prime factors.
Answer: 3×5×7
- 105 = 3 × 35
- 35 = 5 × 7
- So 105 = 3 × 5 × 7
2.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
3.Use a factor tree to write 180 as a product of prime factors.
Answer: 2×2×3×3×5
- 180 = 2 × 90
- 90 = 2 × 45
- 45 = 3 × 15
- 15 = 3 × 5
- So 180 = 2 × 2 × 3 × 3 × 5 = 22 × 32 × 5
4.Which number has the prime factorisation 2 × 3 × 5 × 7?
Answer: 210
- 2 × 3 × 5 × 7 = 210
5.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
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 36 as a product of prime factors.
Answer: 2×2×3×3
- 36 = 2 × 18
- 18 = 2 × 9
- 9 = 3 × 3
- So 36 = 2 × 2 × 3 × 3 = 22 × 32
8.Which number has the prime factorisation 3 × 5 × 7?
Answer: 105
- 3 × 5 × 7 = 105
Marking tips
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