FreeMath
Grade 4medium

Prime and Composite Numbers Practice

Practice identifying prime numbers (only divisible by 1 and itself) and composite numbers (have more than two factors). Remember: 1 is neither prime nor composite.

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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.Is 7 prime or composite?
  2. 2.Is 12 prime or composite?
  3. 3.Is 23 prime or composite?
  4. 4.Is 15 prime or composite?
  5. 5.Is 2 prime or composite?
  6. 6.Is 21 prime or composite?
  7. 7.Is 17 prime or composite?
  8. 8.Is 9 prime or composite?
  9. 9.Is 29 prime or composite?
  10. 10.Is 25 prime or composite?
  11. 11.Is 31 prime or composite?
  12. 12.Is 27 prime or composite?
  13. 13.Is 13 prime or composite?
  14. 14.Is 18 prime or composite?
  15. 15.Is 37 prime or composite?
  16. 16.Is 33 prime or composite?
  17. 17.Is 41 prime or composite?
  18. 18.Is 49 prime or composite?
  19. 19.Is 43 prime or composite?
  20. 20.Is 51 prime or composite?
Show answer key
  1. 1.Is 7 prime or composite? Answer: Prime
  2. 2.Is 12 prime or composite? Answer: Composite
  3. 3.Is 23 prime or composite? Answer: Prime
  4. 4.Is 15 prime or composite? Answer: Composite
  5. 5.Is 2 prime or composite? Answer: Prime
  6. 6.Is 21 prime or composite? Answer: Composite
  7. 7.Is 17 prime or composite? Answer: Prime
  8. 8.Is 9 prime or composite? Answer: Composite
  9. 9.Is 29 prime or composite? Answer: Prime
  10. 10.Is 25 prime or composite? Answer: Composite
  11. 11.Is 31 prime or composite? Answer: Prime
  12. 12.Is 27 prime or composite? Answer: Composite
  13. 13.Is 13 prime or composite? Answer: Prime
  14. 14.Is 18 prime or composite? Answer: Composite
  15. 15.Is 37 prime or composite? Answer: Prime
  16. 16.Is 33 prime or composite? Answer: Composite
  17. 17.Is 41 prime or composite? Answer: Prime
  18. 18.Is 49 prime or composite? Answer: Composite
  19. 19.Is 43 prime or composite? Answer: Prime
  20. 20.Is 51 prime or composite? Answer: Composite

About This Practice

This practice set includes 20 classification problems. Understanding prime and composite numbers is essential for factoring and number theory.

Want more practice? See all Grade 4 practice →