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HCF and LCM Worksheet

Quantitative aptitude lesson 1: HCF and LCM · Set 477 · 40 questions
TalentJR

The method (Prime factors): Write each number as a product of primes: 36 = 2 × 2 × 3 × 3. HCF: multiply the primes the numbers share (each as many times as it appears in both). LCM: take every prime the greatest number of times it appears. For two numbers, HCF × LCM = first number × second number.

NameDateTime takenScore ___ / 40
  1. 1.Find the LCM of 20 and 28.
  2. 2.Find the LCM of 12 and 16.
  3. 3.Find the LCM of 6 and 5.
  4. 4.The HCF of two numbers is 6 and their LCM is 252. One of the numbers is 42. What is the other number?
  5. 5.Find the HCF of 6 and 21.
  6. 6.Find the LCM of 7 and 8.
  7. 7.The HCF of two numbers is 8 and their LCM is 120. One of the numbers is 40. What is the other number?
  8. 8.The HCF of two numbers is 8 and their LCM is 96. One of the numbers is 24. What is the other number?
  9. 9.Find the LCM of 14, 4 and 3.
  10. 10.Find the LCM of 18 and 21.
  11. 11.Find the LCM of 54 and 42.
  12. 12.Find the LCM of 7 and 9.
  13. 13.Find the LCM of 27 and 12.
  14. 14.Find the LCM of 8 and 7.
  15. 15.The HCF of two numbers is 3 and their LCM is 120. One of the numbers is 24. What is the other number?
  16. 16.The HCF of two numbers is 5 and their LCM is 280. One of the numbers is 40. What is the other number?
  17. 17.The HCF of two numbers is 3 and their LCM is 30. One of the numbers is 15. What is the other number?
  18. 18.Find the HCF of 30 and 40.
  19. 19.Find the LCM of 21 and 15.
  20. 20.The HCF of two numbers is 2 and their LCM is 30. One of the numbers is 6. What is the other number?
  21. 21.Find the LCM of 6 and 10.
  22. 22.Find the HCF of 24 and 42.
  23. 23.Find the LCM of 2, 8 and 3.
  24. 24.The HCF of two numbers is 3 and their LCM is 108. One of the numbers is 12. What is the other number?
  25. 25.Find the HCF of 72 and 81.
  26. 26.The HCF of two numbers is 7 and their LCM is 245. One of the numbers is 35. What is the other number?
  27. 27.Find the LCM of 10 and 35.
  28. 28.Find the LCM of 2, 12 and 6.
  29. 29.Find the LCM of 4, 11 and 10.
  30. 30.Find the LCM of 15, 5 and 14.
  31. 31.The HCF of two numbers is 3 and their LCM is 168. One of the numbers is 21. What is the other number?
  32. 32.Find the HCF of 48 and 30.
  33. 33.Find the HCF of 30 and 80.
  34. 34.The HCF of two numbers is 7 and their LCM is 105. One of the numbers is 35. What is the other number?
  35. 35.Find the HCF of 42 and 56.
  36. 36.Find the HCF of 50 and 20.
  37. 37.Find the LCM of 5, 12 and 2.
  38. 38.The HCF of two numbers is 4 and their LCM is 24. One of the numbers is 12. What is the other number?
  39. 39.Find the HCF of 42 and 98.
  40. 40.Find the LCM of 36 and 28.

Answer key

  1. 140
  2. 48
  3. 30
  4. 36
  5. 3
  6. 56
  7. 24
  8. 32
  9. 84
  10. 126
  11. 378
  12. 63
  13. 108
  14. 56
  15. 15
  16. 35
  17. 6
  18. 10
  19. 105
  20. 10
  21. 30
  22. 6
  23. 24
  24. 27
  25. 9
  26. 49
  27. 70
  28. 12
  29. 220
  30. 210
  31. 24
  32. 6
  33. 10
  34. 21
  35. 14
  36. 10
  37. 60
  38. 8
  39. 14
  40. 252

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