Year 7 Prime Factorisation (Factor Trees) Worksheet — Level 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 — 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 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
2.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
3.Use a factor tree to write 135 as a product of prime factors.
Answer: 3×3×3×5
- 135 = 3 × 45
- 45 = 3 × 15
- 15 = 3 × 5
- So 135 = 3 × 3 × 3 × 5 = 33 × 5
4.Which number has the prime factorisation 2 × 33 × 5?
Answer: 270
- 2 × 3 × 3 × 3 × 5 = 270
5.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
6.Use a factor tree to write 162 as a product of prime factors.
Answer: 2×3×3×3×3
- 162 = 2 × 81
- 81 = 3 × 27
- 27 = 3 × 9
- 9 = 3 × 3
- So 162 = 2 × 3 × 3 × 3 × 3 = 2 × 34
7.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
8.Which number has the prime factorisation 23 × 3 × 7?
Answer: 168
- 2 × 2 × 2 × 3 × 7 = 168
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