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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 48 · 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.Which of these is a perfect cube? (a) 1749 (b) 1728 (c) 1750
  2. 2.Which of these is a perfect cube? (a) 47 (b) 27 (c) 38
  3. 3.What is ∛64? =
  4. 4.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  5. 5.What is the smallest whole number by which 72 must be multiplied to get a perfect cube?
  6. 6.Which of these is a perfect cube? (a) 2436 (b) 2212 (c) 2197
  7. 7.What is 13³? =
  8. 8.What is 18³? =
  9. 9.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  10. 10.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  11. 11.What is 4³? =
  12. 12.What is ∛10648? =
  13. 13.Which of these is a perfect cube? (a) 239 (b) 216 (c) 296
  14. 14.What is 10³? =
  15. 15.Which of these is a perfect cube? (a) 729 (b) 787 (c) 759
  16. 16.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  17. 17.Which of these is a perfect cube? (a) 82 (b) 64 (c) 81
  18. 18.What is 6³? =
  19. 19.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  20. 20.Which of these is a perfect cube? (a) 3375 (b) 3699 (c) 3965
  21. 21.What is ∛8? =
  22. 22.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  23. 23.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  24. 24.What is 9³? =
  25. 25.What is ∛4913? =
  26. 26.What is ∛13824? =
  27. 27.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  28. 28.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  29. 29.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  30. 30.Which of these is a perfect cube? (a) 353 (b) 343 (c) 382
  31. 31.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  32. 32.What is ∛125? =
  33. 33.What is 15³? =
  34. 34.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  35. 35.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  36. 36.What is ∛216? =
  37. 37.What is ∛512? =
  38. 38.What is 20³? =
  39. 39.What is ∛15625? =
  40. 40.What is ∛2197? =

Answer key

  1. 1728
  2. 27
  3. 4
  4. 8
  5. 3
  6. 2197
  7. 2197
  8. 5832
  9. 2
  10. 2
  11. 64
  12. 22
  13. 216
  14. 1000
  15. 729
  16. 9
  17. 64
  18. 216
  19. 64
  20. 3375
  21. 2
  22. 15
  23. 7
  24. 729
  25. 17
  26. 24
  27. 64
  28. 14
  29. 25
  30. 343
  31. 3
  32. 5
  33. 3375
  34. 8
  35. 216
  36. 6
  37. 8
  38. 8000
  39. 25
  40. 13

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