Year 7 Prime Factorisation (Factor Trees) Worksheet — Level 3 — 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 3 — Answers
Keep splitting each number into two factors until every branch ends in a prime. Write repeated factors with an index, e.g. 2 × 2 × 2 = 23.
1.Use a factor tree to write 297 as a product of prime factors in index form.
Answer: 33×11
- 297 = 3 × 99
- 99 = 3 × 33
- 33 = 3 × 11
- So 297 = 3 × 3 × 3 × 11 = 33 × 11
2.Which number has the prime factorisation 32 × 11?
Answer: 99
- 3 × 3 × 11 = 99
3.Use a factor tree to write 88 as a product of prime factors in index form.
Answer: 23×11
- 88 = 2 × 44
- 44 = 2 × 22
- 22 = 2 × 11
- So 88 = 2 × 2 × 2 × 11 = 23 × 11
4.Which number has the prime factorisation 2 × 3 × 7 × 11?
Answer: 462
- 2 × 3 × 7 × 11 = 462
5.Use a factor tree to write 147 as a product of prime factors in index form.
Answer: 3×72
- 147 = 3 × 49
- 49 = 7 × 7
- So 147 = 3 × 7 × 7 = 3 × 72
6.Which number has the prime factorisation 3 × 7 × 11?
Answer: 231
- 3 × 7 × 11 = 231
7.Use a factor tree to write 250 as a product of prime factors in index form.
Answer: 2×53
- 250 = 2 × 125
- 125 = 5 × 25
- 25 = 5 × 5
- So 250 = 2 × 5 × 5 × 5 = 2 × 53
8.Which number has the prime factorisation 3 × 52?
Answer: 75
- 3 × 5 × 5 = 75
Marking tips
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