5th Grade Prime Factorization (Factor Trees) Worksheet — Level 3 — 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 — 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 693 as a product of prime factors in index form.
Answer: 32×7×11
- 693 = 3 × 231
- 231 = 3 × 77
- 77 = 7 × 11
- So 693 = 3 × 3 × 7 × 11 = 32 × 7 × 11
2.Which number has the prime factorization 2 × 72?
Answer: 98
- 2 × 7 × 7 = 98
3.Use a factor tree to write 231 as a product of prime factors in index form.
Answer: 3×7×11
- 231 = 3 × 77
- 77 = 7 × 11
- So 231 = 3 × 7 × 11 = 3 × 7 × 11
4.Which number has the prime factorization 22 × 52?
Answer: 100
- 2 × 2 × 5 × 5 = 100
5.Use a factor tree to write 500 as a product of prime factors in index form.
Answer: 22×53
- 500 = 2 × 250
- 250 = 2 × 125
- 125 = 5 × 25
- 25 = 5 × 5
- So 500 = 2 × 2 × 5 × 5 × 5 = 22 × 53
6.Which number has the prime factorization 3 × 5 × 72?
Answer: 735
- 3 × 5 × 7 × 7 = 735
7.Use a factor tree to write 140 as a product of prime factors in index form.
Answer: 22×5×7
- 140 = 2 × 70
- 70 = 2 × 35
- 35 = 5 × 7
- So 140 = 2 × 2 × 5 × 7 = 22 × 5 × 7
8.Which number has the prime factorization 5 × 112?
Answer: 605
- 5 × 11 × 11 = 605
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
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