FreeMath
Grade 5medium

Greatest Common Factor (GCF) Practice

Practice finding the Greatest Common Factor (GCF) of two numbers. The GCF is the largest number that divides evenly into both numbers.

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All 20 Practice Problems

Every question in this set. Solve them on paper, or use the interactive tool above for instant feedback and hints.

  1. 1.Find the GCF of 12 and 18
  2. 2.Find the GCF of 15 and 25
  3. 3.Find the GCF of 20 and 30
  4. 4.Find the GCF of 24 and 36
  5. 5.Find the GCF of 28 and 42
  6. 6.Find the GCF of 32 and 48
  7. 7.Find the GCF of 36 and 54
  8. 8.Find the GCF of 40 and 60
  9. 9.Find the GCF of 45 and 75
  10. 10.Find the GCF of 48 and 72
  11. 11.Find the GCF of 14 and 21
  12. 12.Find the GCF of 16 and 24
  13. 13.Find the GCF of 18 and 27
  14. 14.Find the GCF of 21 and 35
  15. 15.Find the GCF of 24 and 32
  16. 16.Find the GCF of 30 and 42
  17. 17.Find the GCF of 35 and 49
  18. 18.Find the GCF of 42 and 56
  19. 19.Find the GCF of 50 and 75
  20. 20.Find the GCF of 56 and 84
Show answer key
  1. 1.Find the GCF of 12 and 18 Answer: 6
  2. 2.Find the GCF of 15 and 25 Answer: 5
  3. 3.Find the GCF of 20 and 30 Answer: 10
  4. 4.Find the GCF of 24 and 36 Answer: 12
  5. 5.Find the GCF of 28 and 42 Answer: 14
  6. 6.Find the GCF of 32 and 48 Answer: 16
  7. 7.Find the GCF of 36 and 54 Answer: 18
  8. 8.Find the GCF of 40 and 60 Answer: 20
  9. 9.Find the GCF of 45 and 75 Answer: 15
  10. 10.Find the GCF of 48 and 72 Answer: 24
  11. 11.Find the GCF of 14 and 21 Answer: 7
  12. 12.Find the GCF of 16 and 24 Answer: 8
  13. 13.Find the GCF of 18 and 27 Answer: 9
  14. 14.Find the GCF of 21 and 35 Answer: 7
  15. 15.Find the GCF of 24 and 32 Answer: 8
  16. 16.Find the GCF of 30 and 42 Answer: 6
  17. 17.Find the GCF of 35 and 49 Answer: 7
  18. 18.Find the GCF of 42 and 56 Answer: 14
  19. 19.Find the GCF of 50 and 75 Answer: 25
  20. 20.Find the GCF of 56 and 84 Answer: 28

About This Practice

This practice set includes 20 GCF problems. Finding the GCF is essential for simplifying fractions and solving problems involving common divisors.

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