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HCF and LCM Worksheet

Quantitative aptitude lesson 1: HCF and LCM · Set 251 · 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 126. One of the numbers is 14. What is the other number?
  2. 2.Find the LCM of 21 and 6.
  3. 3.Find the LCM of 10, 4 and 2.
  4. 4.Find the LCM of 14, 9 and 6.
  5. 5.Find the HCF of 81 and 45.
  6. 6.Find the HCF of 24 and 30.
  7. 7.Find the HCF of 22 and 77.
  8. 8.Find the LCM of 5 and 6.
  9. 9.Find the LCM of 30 and 35.
  10. 10.Find the HCF of 28 and 32.
  11. 11.Find the HCF of 50 and 30.
  12. 12.Find the LCM of 48 and 18.
  13. 13.Find the LCM of 4, 10 and 14.
  14. 14.The HCF of two numbers is 4 and their LCM is 160. One of the numbers is 20. What is the other number?
  15. 15.Find the LCM of 15 and 27.
  16. 16.Find the HCF of 24 and 32.
  17. 17.Find the LCM of 4, 15 and 3.
  18. 18.The HCF of two numbers is 9 and their LCM is 54. One of the numbers is 18. What is the other number?
  19. 19.Find the HCF of 45 and 75.
  20. 20.Find the LCM of 10 and 8.
  21. 21.The HCF of two numbers is 3 and their LCM is 84. One of the numbers is 21. What is the other number?
  22. 22.Find the LCM of 3, 8 and 14.
  23. 23.The HCF of two numbers is 7 and their LCM is 210. One of the numbers is 35. What is the other number?
  24. 24.Find the HCF of 84 and 98.
  25. 25.The HCF of two numbers is 9 and their LCM is 252. One of the numbers is 63. What is the other number?
  26. 26.Find the LCM of 14 and 8.
  27. 27.The HCF of two numbers is 7 and their LCM is 168. One of the numbers is 21. What is the other number?
  28. 28.Find the HCF of 35 and 45.
  29. 29.Find the LCM of 8 and 7.
  30. 30.Find the HCF of 36 and 32.
  31. 31.Find the HCF of 60 and 45.
  32. 32.Find the LCM of 6, 12 and 10.
  33. 33.Find the LCM of 9 and 21.
  34. 34.Find the LCM of 10, 6 and 7.
  35. 35.Find the LCM of 2, 7 and 13.
  36. 36.Find the LCM of 18 and 24.
  37. 37.Find the HCF of 78 and 65.
  38. 38.Find the HCF of 26 and 39.
  39. 39.The HCF of two numbers is 6 and their LCM is 90. One of the numbers is 30. What is the other number?
  40. 40.Find the HCF of 6 and 21.

Answer key

  1. 63
  2. 42
  3. 20
  4. 126
  5. 9
  6. 6
  7. 11
  8. 30
  9. 210
  10. 4
  11. 10
  12. 144
  13. 140
  14. 32
  15. 135
  16. 8
  17. 60
  18. 27
  19. 15
  20. 40
  21. 12
  22. 168
  23. 42
  24. 14
  25. 36
  26. 56
  27. 56
  28. 5
  29. 56
  30. 4
  31. 15
  32. 60
  33. 63
  34. 210
  35. 182
  36. 72
  37. 13
  38. 13
  39. 18
  40. 3

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