7th Grade Prime Factorization (Factor Trees) Worksheet — Level 3 — Practice Set 4 — Answers
Answer sheet with worked solutions for the 7th Grade factors, multiples & primes worksheet.
Success TutoringWorksheetsAnswer sheet7th Grade · Mathematics · Factors, Multiples & Primes7th Grade Prime Factorization (Factor Trees) Worksheet — Level 3 — Practice Set 4 — 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 180 as a product of prime factors in index form.
Answer: 22×32×5
- 180 = 2 × 90
- 90 = 2 × 45
- 45 = 3 × 15
- 15 = 3 × 5
- So 180 = 2 × 2 × 3 × 3 × 5 = 22 × 32 × 5
2.Which number has the prime factorization 22 × 52?
Answer: 100
- 2 × 2 × 5 × 5 = 100
3.Use a factor tree to write 980 as a product of prime factors in index form.
Answer: 22×5×72
- 980 = 2 × 490
- 490 = 2 × 245
- 245 = 5 × 49
- 49 = 7 × 7
- So 980 = 2 × 2 × 5 × 7 × 7 = 22 × 5 × 72
4.Which number has the prime factorization 3 × 112?
Answer: 363
- 3 × 11 × 11 = 363
5.Use a factor tree to write 90 as a product of prime factors in index form.
Answer: 2×32×5
- 90 = 2 × 45
- 45 = 3 × 15
- 15 = 3 × 5
- So 90 = 2 × 3 × 3 × 5 = 2 × 32 × 5
6.Which number has the prime factorization 22 × 3 × 7 × 11?
Answer: 924
- 2 × 2 × 3 × 7 × 11 = 924
7.Use a factor tree to write 210 as a product of prime factors in index form.
Answer: 2×3×5×7
- 210 = 2 × 105
- 105 = 3 × 35
- 35 = 5 × 7
- So 210 = 2 × 3 × 5 × 7 = 2 × 3 × 5 × 7
8.Which number has the prime factorization 2 × 32 × 72?
Answer: 882
- 2 × 3 × 3 × 7 × 7 = 882
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