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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 210 · 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 big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  2. 2.What is ∛4096? =
  3. 3.Which of these is a perfect cube? (a) 75 (b) 74 (c) 64
  4. 4.What is the smallest whole number by which 625 must be divided to get a perfect cube?
  5. 5.What is 10³? =
  6. 6.What is ∛343? =
  7. 7.What is 18³? =
  8. 8.What is 20³? =
  9. 9.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  11. 11.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  12. 12.What is ∛10648? =
  13. 13.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  14. 14.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  15. 15.What is 5³? =
  16. 16.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
  17. 17.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  18. 18.Which of these is a perfect cube? (a) 1076 (b) 1215 (c) 1000
  19. 19.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  20. 20.What is 14³? =
  21. 21.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  22. 22.Which of these is a perfect cube? (a) 3484 (b) 3375 (c) 3520
  23. 23.What is 13³? =
  24. 24.What is ∛9261? =
  25. 25.What is 3³? =
  26. 26.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  27. 27.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  28. 28.What is 16³? =
  29. 29.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  30. 30.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  31. 31.What is the smallest whole number by which 25 must be divided 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 ∛4913? =
  34. 34.What is ∛1728? =
  35. 35.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  36. 36.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  37. 37.What is ∛8000? =
  38. 38.What is 15³? =
  39. 39.Which of these is a perfect cube? (a) 937 (b) 729 (c) 928
  40. 40.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?

Answer key

  1. 27
  2. 16
  3. 64
  4. 5
  5. 1000
  6. 7
  7. 5832
  8. 8000
  9. 125
  10. 15
  11. 4
  12. 22
  13. 4
  14. 2
  15. 125
  16. 9
  17. 10
  18. 1000
  19. 3
  20. 2744
  21. 8
  22. 3375
  23. 2197
  24. 21
  25. 27
  26. 49
  27. 11
  28. 4096
  29. 25
  30. 64
  31. 25
  32. 19
  33. 17
  34. 12
  35. 216
  36. 5
  37. 20
  38. 3375
  39. 729
  40. 8

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