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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 522 · 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.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  2. 2.What is ∛729? =
  3. 3.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  4. 4.What is 5³? =
  5. 5.What is ∛125? =
  6. 6.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  7. 7.What is ∛27? =
  8. 8.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  9. 9.What is ∛343? =
  10. 10.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  11. 11.What is 10³? =
  12. 12.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  13. 13.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  14. 14.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  15. 15.Which of these is a perfect cube? (a) 34 (b) 27 (c) 42
  16. 16.What is ∛64? =
  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.What is ∛15625? =
  20. 20.Which of these is a perfect cube? (a) 3115 (b) 2788 (c) 2744
  21. 21.What is the smallest whole number by which 675 must be divided to get a perfect cube?
  22. 22.What is the smallest whole number by which 648 must be multiplied to get a perfect cube?
  23. 23.What is ∛216? =
  24. 24.What is 13³? =
  25. 25.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  26. 26.Which of these is a perfect cube? (a) 343 (b) 463 (c) 386
  27. 27.Which of these is a perfect cube? (a) 2197 (b) 2377 (c) 2590
  28. 28.What is 19³? =
  29. 29.What is ∛9261? =
  30. 30.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  31. 31.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  32. 32.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  33. 33.Which of these is a perfect cube? (a) 3375 (b) 3493 (c) 3827
  34. 34.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  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 4³? =
  37. 37.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  38. 38.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  39. 39.What is ∛1000? =
  40. 40.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?

Answer key

  1. 125
  2. 9
  3. 9
  4. 125
  5. 5
  6. 7
  7. 3
  8. 27
  9. 7
  10. 125
  11. 1000
  12. 8
  13. 11
  14. 15
  15. 27
  16. 4
  17. 8
  18. 12
  19. 25
  20. 2744
  21. 25
  22. 9
  23. 6
  24. 2197
  25. 17
  26. 343
  27. 2197
  28. 6859
  29. 21
  30. 9
  31. 27
  32. 14
  33. 3375
  34. 2
  35. 216
  36. 64
  37. 18
  38. 7
  39. 10
  40. 20

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