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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 359 · 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 8000 cubic cm. How long is each edge (in cm)?
  2. 2.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  3. 3.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  4. 4.What is ∛10648? =
  5. 5.Which of these is a perfect cube? (a) 39 (b) 54 (c) 27
  6. 6.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  7. 7.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  8. 8.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  9. 9.What is 3³? =
  10. 10.What is 5³? =
  11. 11.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  12. 12.Which of these is a perfect cube? (a) 965 (b) 729 (c) 730
  13. 13.Which of these is a perfect cube? (a) 3451 (b) 3375 (c) 3612
  14. 14.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  15. 15.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  16. 16.What is ∛343? =
  17. 17.What is the smallest whole number by which 500 must be divided to get a perfect cube?
  18. 18.Which of these is a perfect cube? (a) 3028 (b) 2966 (c) 2744
  19. 19.Which of these is a perfect cube? (a) 2197 (b) 2216 (c) 2498
  20. 20.What is 4³? =
  21. 21.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  22. 22.What is ∛2744? =
  23. 23.What is ∛13824? =
  24. 24.What is ∛5832? =
  25. 25.What is ∛1331? =
  26. 26.What is ∛27? =
  27. 27.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  28. 28.What is 11³? =
  29. 29.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  30. 30.What is 15³? =
  31. 31.What is 14³? =
  32. 32.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  33. 33.Which of these is a perfect cube? (a) 154 (b) 176 (c) 125
  34. 34.What is ∛216? =
  35. 35.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  36. 36.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  37. 37.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  38. 38.What is the smallest whole number by which 243 must be multiplied to get a perfect cube?
  39. 39.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  40. 40.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?

Answer key

  1. 20
  2. 9
  3. 27
  4. 22
  5. 27
  6. 2
  7. 5
  8. 4
  9. 27
  10. 125
  11. 9
  12. 729
  13. 3375
  14. 125
  15. 16
  16. 7
  17. 4
  18. 2744
  19. 2197
  20. 64
  21. 10
  22. 14
  23. 24
  24. 18
  25. 11
  26. 3
  27. 2
  28. 1331
  29. 49
  30. 3375
  31. 2744
  32. 9
  33. 125
  34. 6
  35. 19
  36. 9
  37. 2
  38. 3
  39. 27
  40. 64

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