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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 743 · 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 cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  2. 2.What is ∛216? =
  3. 3.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  4. 4.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  5. 5.What is ∛5832? =
  6. 6.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  7. 7.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  8. 8.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  9. 9.What is ∛1000? =
  10. 10.What is ∛4096? =
  11. 11.Which of these is a perfect cube? (a) 3375 (b) 3867 (c) 3778
  12. 12.Which of these is a perfect cube? (a) 370 (b) 343 (c) 375
  13. 13.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  14. 14.What is ∛27? =
  15. 15.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  16. 16.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  17. 17.What is 14³? =
  18. 18.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  19. 19.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  20. 20.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  21. 21.What is 17³? =
  22. 22.What is 9³? =
  23. 23.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  24. 24.What is ∛6859? =
  25. 25.Which of these is a perfect cube? (a) 44 (b) 43 (c) 27
  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 the smallest whole number by which 192 must be divided to get a perfect cube?
  28. 28.Which of these is a perfect cube? (a) 512 (b) 537 (c) 603
  29. 29.What is 15³? =
  30. 30.What is 18³? =
  31. 31.What is 3³? =
  32. 32.What is 13³? =
  33. 33.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  34. 34.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  35. 35.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  36. 36.Which of these is a perfect cube? (a) 1155 (b) 1269 (c) 1000
  37. 37.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  38. 38.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  39. 39.Which of these is a perfect cube? (a) 2690 (b) 2509 (c) 2197
  40. 40.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?

Answer key

  1. 10
  2. 6
  3. 3
  4. 19
  5. 18
  6. 9
  7. 20
  8. 64
  9. 10
  10. 16
  11. 3375
  12. 343
  13. 2
  14. 3
  15. 8
  16. 4
  17. 2744
  18. 49
  19. 27
  20. 5
  21. 4913
  22. 729
  23. 4
  24. 19
  25. 27
  26. 216
  27. 3
  28. 512
  29. 3375
  30. 5832
  31. 27
  32. 2197
  33. 216
  34. 3
  35. 11
  36. 1000
  37. 7
  38. 13
  39. 2197
  40. 25

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