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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 725 · 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.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  3. 3.What is ∛64? =
  4. 4.What is 8³? =
  5. 5.What is the smallest whole number by which 1080 must be divided to get a perfect cube?
  6. 6.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  7. 7.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  8. 8.What is ∛343? =
  9. 9.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  10. 10.What is 10³? =
  11. 11.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  12. 12.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  13. 13.A cube has a volume of 4096 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.What is ∛5832? =
  16. 16.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  17. 17.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  18. 18.What is 9³? =
  19. 19.Which of these is a perfect cube? (a) 413 (b) 343 (c) 372
  20. 20.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  21. 21.What is 15³? =
  22. 22.What is 13³? =
  23. 23.What is 14³? =
  24. 24.Which of these is a perfect cube? (a) 108 (b) 64 (c) 94
  25. 25.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  26. 26.Which of these is a perfect cube? (a) 50 (b) 44 (c) 27
  27. 27.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  28. 28.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  29. 29.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  30. 30.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  31. 31.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  32. 32.What is ∛4913? =
  33. 33.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
  34. 34.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  35. 35.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  36. 36.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  37. 37.What is 4³? =
  38. 38.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  39. 39.What is the smallest whole number by which 250 must be divided to get a perfect cube?
  40. 40.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?

Answer key

  1. 4096
  2. 27
  3. 4
  4. 512
  5. 5
  6. 64
  7. 5
  8. 7
  9. 216
  10. 1000
  11. 8
  12. 18
  13. 16
  14. 15
  15. 18
  16. 14
  17. 11
  18. 729
  19. 343
  20. 49
  21. 3375
  22. 2197
  23. 2744
  24. 64
  25. 8
  26. 27
  27. 216
  28. 4
  29. 3
  30. 4
  31. 64
  32. 17
  33. 7
  34. 64
  35. 4
  36. 216
  37. 64
  38. 17
  39. 2
  40. 9

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