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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 740 · 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 16³? =
  2. 2.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  3. 3.What is ∛12167? =
  4. 4.What is ∛10648? =
  5. 5.What is ∛4096? =
  6. 6.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  7. 7.What is 15³? =
  8. 8.Which of these is a perfect cube? (a) 3816 (b) 3375 (c) 3819
  9. 9.Which of these is a perfect cube? (a) 108 (b) 107 (c) 64
  10. 10.Which of these is a perfect cube? (a) 660 (b) 512 (c) 529
  11. 11.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  12. 12.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  13. 13.Which of these is a perfect cube? (a) 343 (b) 485 (c) 454
  14. 14.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  15. 15.What is ∛6859? =
  16. 16.What is ∛4913? =
  17. 17.What is ∛512? =
  18. 18.What is the smallest whole number by which 875 must be divided to get a perfect cube?
  19. 19.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  20. 20.What is 17³? =
  21. 21.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  22. 22.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  23. 23.What is ∛8000? =
  24. 24.What is 13³? =
  25. 25.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  26. 26.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  27. 27.What is ∛1728? =
  28. 28.What is the smallest whole number by which 625 must be divided to get a perfect cube?
  29. 29.What is the smallest whole number by which 1080 must be divided to get a perfect cube?
  30. 30.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  31. 31.What is 6³? =
  32. 32.What is ∛216? =
  33. 33.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  34. 34.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  35. 35.What is 3³? =
  36. 36.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  37. 37.What is ∛13824? =
  38. 38.What is 20³? =
  39. 39.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  40. 40.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?

Answer key

  1. 4096
  2. 9
  3. 23
  4. 22
  5. 16
  6. 216
  7. 3375
  8. 3375
  9. 64
  10. 512
  11. 8
  12. 2
  13. 343
  14. 6
  15. 19
  16. 17
  17. 8
  18. 7
  19. 125
  20. 4913
  21. 5
  22. 25
  23. 20
  24. 2197
  25. 2
  26. 14
  27. 12
  28. 5
  29. 5
  30. 64
  31. 216
  32. 6
  33. 3
  34. 5
  35. 27
  36. 64
  37. 24
  38. 8000
  39. 216
  40. 216

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