Prime Factorization Worksheets
Write each number as a product of prime factors.
Prime Factorization
Name:Date:Score:
Write each number as a product of prime factors. (Tip: draw a factor tree.)
- 194 =
- 256 =
- 393 =
- 410 =
- 528 =
- 68 =
- 726 =
- 835 =
- 980 =
- 1032 =
Printable Worksheets for Kids · printableworksheetsforkids.pages.dev
Prime Factorization
Name:Date:Score:
Write each number as a product of prime factors. (Tip: draw a factor tree.)
- 187 =
- 221 =
- 391 =
- 420 =
- 575 =
- 682 =
- 756 =
- 878 =
- 992 =
- 1054 =
Printable Worksheets for Kids · printableworksheetsforkids.pages.dev
Prime Factorization
Name:Date:Score:
Write each number as a product of prime factors. (Tip: draw a factor tree.)
- 1100 =
- 250 =
- 380 =
- 414 =
- 545 =
- 615 =
- 742 =
- 830 =
- 990 =
- 1078 =
Printable Worksheets for Kids · printableworksheetsforkids.pages.dev
Answer key — Sheet A (10 answers)
- 1. 2 × 47
- 2. 2 × 2 × 2 × 7
- 3. 3 × 31
- 4. 2 × 5
- 5. 2 × 2 × 7
- 6. 2 × 2 × 2
- 7. 2 × 13
- 8. 5 × 7
- 9. 2 × 2 × 2 × 2 × 5
- 10. 2 × 2 × 2 × 2 × 2
Answer key — Sheet B (10 answers)
- 1. 3 × 29
- 2. 3 × 7
- 3. 7 × 13
- 4. 2 × 2 × 5
- 5. 3 × 5 × 5
- 6. 2 × 41
- 7. 2 × 2 × 2 × 7
- 8. 2 × 3 × 13
- 9. 2 × 2 × 23
- 10. 2 × 3 × 3 × 3
Answer key — Sheet C (10 answers)
- 1. 2 × 2 × 5 × 5
- 2. 2 × 5 × 5
- 3. 2 × 2 × 2 × 2 × 5
- 4. 2 × 7
- 5. 3 × 3 × 5
- 6. 3 × 5
- 7. 2 × 3 × 7
- 8. 2 × 3 × 5
- 9. 2 × 3 × 3 × 5
- 10. 2 × 3 × 13
About this skill
A factor tree breaks a number down until every branch ends in a prime. The final list is unique for each number.
How to teach it
- List factors in pairs, working from 1 upwards until the pairs meet.
- Use a factor tree for prime factorisation.
- Learn the divisibility rules for 2, 3, 5, 9 and 10 first.
Mistakes to watch for
- Missing factor pairs or listing a factor twice.
- Calling 1 a prime or treating 9 as prime.
Where to go next
- Greatest Common Factor (GCF)G5, G6 · Factoring & Prime Factors
- Least Common Multiple (LCM)G5, G6 · Factoring & Prime Factors
- Divisibility RulesG4, G5 · Factoring & Prime Factors
- Factors of a NumberG4 · Factoring & Prime Factors
- Prime and Composite NumbersG4, G5 · Factoring & Prime Factors
- MultiplesG3, G4 · Factoring & Prime Factors
