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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 101 · 40 sums
TalentJR

The method (Threes make cubes): Cube: n × n × n. Cube root: the number that, used three times, gives the cube. Units digits: 1→1, 2→8, 3→7, 4→4, 5→5, 6→6, 7→3, 8→2, 9→9, 0→0 — use them to guess cube roots. Make a perfect cube: break into primes; multiply by what completes each group of three (or divide by what is left over). A big cube of edge a cut into small cubes of edge b gives (a ÷ b)³ small cubes.

NameDateTime takenScore ___ / 40
  1. 1.What is ∛8000? =
  2. 2.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  3. 3.What is 20³? =
  4. 4.What is ∛343? =
  5. 5.Which of these is a perfect cube? (a) 79 (b) 64 (c) 70
  6. 6.What is ∛2197? =
  7. 7.What is 11³? =
  8. 8.Which of these is a perfect cube? (a) 1603 (b) 1331 (c) 1598
  9. 9.Which of these is a perfect cube? (a) 1000 (b) 1049 (c) 1045
  10. 10.Which of these is a perfect cube? (a) 305 (b) 251 (c) 216
  11. 11.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  12. 12.What is 18³? =
  13. 13.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  14. 14.Which of these is a perfect cube? (a) 2744 (b) 3211 (c) 2755
  15. 15.What is ∛12167? =
  16. 16.What is ∛4913? =
  17. 17.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  18. 18.What is ∛1728? =
  19. 19.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  20. 20.Which of these is a perfect cube? (a) 28 (b) 27 (c) 37
  21. 21.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  22. 22.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  23. 23.What is ∛512? =
  24. 24.What is ∛9261? =
  25. 25.What is ∛5832? =
  26. 26.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  27. 27.What is ∛15625? =
  28. 28.Which of these is a perfect cube? (a) 1728 (b) 1972 (c) 1885
  29. 29.What is ∛125? =
  30. 30.What is ∛10648? =
  31. 31.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  32. 32.What is 2³? =
  33. 33.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  34. 34.Which of these is a perfect cube? (a) 774 (b) 729 (c) 756
  35. 35.Which of these is a perfect cube? (a) 2197 (b) 2487 (c) 2626
  36. 36.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  37. 37.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  38. 38.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  39. 39.What is ∛13824? =
  40. 40.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?

Answer key

  1. 20
  2. 13
  3. 8000
  4. 7
  5. 64
  6. 13
  7. 1331
  8. 1331
  9. 1000
  10. 216
  11. 125
  12. 5832
  13. 8
  14. 2744
  15. 23
  16. 17
  17. 8
  18. 12
  19. 5
  20. 27
  21. 19
  22. 15
  23. 8
  24. 21
  25. 18
  26. 216
  27. 25
  28. 1728
  29. 5
  30. 22
  31. 4
  32. 8
  33. 216
  34. 729
  35. 2197
  36. 18
  37. 3
  38. 49
  39. 24
  40. 5

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