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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 745 · 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 20³? =
  2. 2.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  3. 3.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  4. 4.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  5. 5.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  7. 7.What is ∛216? =
  8. 8.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  9. 9.What is ∛5832? =
  10. 10.Which of these is a perfect cube? (a) 46 (b) 44 (c) 27
  11. 11.What is 17³? =
  12. 12.What is ∛729? =
  13. 13.What is ∛2197? =
  14. 14.Which of these is a perfect cube? (a) 2980 (b) 2744 (c) 2936
  15. 15.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  16. 16.Which of these is a perfect cube? (a) 1730 (b) 1728 (c) 2029
  17. 17.What is ∛4096? =
  18. 18.Which of these is a perfect cube? (a) 3469 (b) 4042 (c) 3375
  19. 19.What is ∛1728? =
  20. 20.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  21. 21.What is 7³? =
  22. 22.What is ∛13824? =
  23. 23.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  24. 24.What is 6³? =
  25. 25.Which of these is a perfect cube? (a) 83 (b) 84 (c) 64
  26. 26.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  27. 27.What is the smallest whole number by which 24 must be divided to get a perfect cube?
  28. 28.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  29. 29.What is 4³? =
  30. 30.What is ∛8000? =
  31. 31.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  32. 32.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  33. 33.What is ∛2744? =
  34. 34.What is ∛10648? =
  35. 35.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  36. 36.Which of these is a perfect cube? (a) 160 (b) 176 (c) 125
  37. 37.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  38. 38.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  39. 39.What is ∛6859? =
  40. 40.What is 19³? =

Answer key

  1. 8000
  2. 8
  3. 7
  4. 64
  5. 64
  6. 4
  7. 6
  8. 8
  9. 18
  10. 27
  11. 4913
  12. 9
  13. 13
  14. 2744
  15. 7
  16. 1728
  17. 16
  18. 3375
  19. 12
  20. 10
  21. 343
  22. 24
  23. 3
  24. 216
  25. 64
  26. 3
  27. 3
  28. 20
  29. 64
  30. 20
  31. 2
  32. 19
  33. 14
  34. 22
  35. 125
  36. 125
  37. 8
  38. 4
  39. 19
  40. 6859

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