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HCF and LCM Worksheet

Quantitative aptitude lesson 1: HCF and LCM · Set 731 · 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.The HCF of two numbers is 7 and their LCM is 168. One of the numbers is 21. What is the other number?
  2. 2.Find the HCF of 99 and 44.
  3. 3.Find the HCF of 81 and 18.
  4. 4.Find the LCM of 7, 10 and 4.
  5. 5.Find the LCM of 9 and 8.
  6. 6.Find the LCM of 9, 12 and 10.
  7. 7.Find the LCM of 54 and 24.
  8. 8.Find the LCM of 27 and 15.
  9. 9.Find the LCM of 6, 14 and 7.
  10. 10.Find the HCF of 64 and 72.
  11. 11.The HCF of two numbers is 4 and their LCM is 80. One of the numbers is 16. What is the other number?
  12. 12.The HCF of two numbers is 9 and their LCM is 252. One of the numbers is 63. What is the other number?
  13. 13.Find the LCM of 11, 9 and 3.
  14. 14.Find the LCM of 35 and 25.
  15. 15.Find the LCM of 8, 9 and 6.
  16. 16.Find the HCF of 75 and 120.
  17. 17.Find the HCF of 16 and 72.
  18. 18.The HCF of two numbers is 3 and their LCM is 126. One of the numbers is 21. What is the other number?
  19. 19.Find the HCF of 27 and 72.
  20. 20.Find the HCF of 10 and 12.
  21. 21.Find the LCM of 2, 4 and 5.
  22. 22.Find the LCM of 45 and 40.
  23. 23.The HCF of two numbers is 5 and their LCM is 280. One of the numbers is 35. What is the other number?
  24. 24.Find the HCF of 28 and 21.
  25. 25.Find the LCM of 18 and 42.
  26. 26.Find the HCF of 14 and 21.
  27. 27.The HCF of two numbers is 7 and their LCM is 84. One of the numbers is 28. What is the other number?
  28. 28.The HCF of two numbers is 5 and their LCM is 180. One of the numbers is 20. What is the other number?
  29. 29.Find the HCF of 16 and 24.
  30. 30.Find the HCF of 84 and 36.
  31. 31.The HCF of two numbers is 4 and their LCM is 40. One of the numbers is 20. What is the other number?
  32. 32.Find the LCM of 9, 8 and 4.
  33. 33.The HCF of two numbers is 2 and their LCM is 84. One of the numbers is 12. What is the other number?
  34. 34.Find the LCM of 6, 3 and 5.
  35. 35.Find the LCM of 10 and 8.
  36. 36.Find the LCM of 10, 12 and 8.
  37. 37.The HCF of two numbers is 6 and their LCM is 60. One of the numbers is 30. What is the other number?
  38. 38.Find the LCM of 8 and 7.
  39. 39.Find the HCF of 40 and 15.
  40. 40.Find the HCF of 6 and 9.

Answer key

  1. 56
  2. 11
  3. 9
  4. 140
  5. 72
  6. 180
  7. 216
  8. 135
  9. 42
  10. 8
  11. 20
  12. 36
  13. 99
  14. 175
  15. 72
  16. 15
  17. 8
  18. 18
  19. 9
  20. 2
  21. 20
  22. 360
  23. 40
  24. 7
  25. 126
  26. 7
  27. 21
  28. 45
  29. 8
  30. 12
  31. 8
  32. 72
  33. 14
  34. 30
  35. 40
  36. 120
  37. 12
  38. 56
  39. 5
  40. 3

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