5th Grade Prime Factorization (Factor Trees) Worksheet — Level 3 — Practice Set 2 — Answers
Answer sheet with worked solutions for the 5th Grade factors, multiples & primes worksheet.
Success TutoringWorksheetsAnswer sheet5th Grade · Mathematics · Factors, Multiples & Primes5th Grade Prime Factorization (Factor Trees) Worksheet — Level 3 — Practice Set 2 — 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 110 as a product of prime factors in index form.
Answer: 2×5×11
- 110 = 2 × 55
- 55 = 5 × 11
- So 110 = 2 × 5 × 11 = 2 × 5 × 11
2.Which number has the prime factorization 23 × 3 × 5 × 7?
Answer: 840
- 2 × 2 × 2 × 3 × 5 × 7 = 840
3.Use a factor tree to write 198 as a product of prime factors in index form.
Answer: 2×32×11
- 198 = 2 × 99
- 99 = 3 × 33
- 33 = 3 × 11
- So 198 = 2 × 3 × 3 × 11 = 2 × 32 × 11
4.Which number has the prime factorization 23 × 72?
Answer: 392
- 2 × 2 × 2 × 7 × 7 = 392
5.Use a factor tree to write 242 as a product of prime factors in index form.
Answer: 2×112
- 242 = 2 × 121
- 121 = 11 × 11
- So 242 = 2 × 11 × 11 = 2 × 112
6.Which number has the prime factorization 22 × 3 × 5 × 7?
Answer: 420
- 2 × 2 × 3 × 5 × 7 = 420
7.Use a factor tree to write 735 as a product of prime factors in index form.
Answer: 3×5×72
- 735 = 3 × 245
- 245 = 5 × 49
- 49 = 7 × 7
- So 735 = 3 × 5 × 7 × 7 = 3 × 5 × 72
8.Which number has the prime factorization 2 × 73?
Answer: 686
- 2 × 7 × 7 × 7 = 686
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
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