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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 377 · 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 ∛2744? =
  2. 2.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  3. 3.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  4. 4.What is ∛8000? =
  5. 5.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  6. 6.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  7. 7.What is 17³? =
  8. 8.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛9261? =
  10. 10.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  11. 11.What is 6³? =
  12. 12.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  13. 13.What is 9³? =
  14. 14.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  15. 15.What is the smallest whole number by which 189 must be divided to get a perfect cube?
  16. 16.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  17. 17.Which of these is a perfect cube? (a) 393 (b) 343 (c) 403
  18. 18.What is ∛3375? =
  19. 19.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  20. 20.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  21. 21.What is ∛1728? =
  22. 22.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  23. 23.What is 13³? =
  24. 24.Which of these is a perfect cube? (a) 87 (b) 64 (c) 68
  25. 25.What is ∛15625? =
  26. 26.What is ∛1000? =
  27. 27.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  28. 28.Which of these is a perfect cube? (a) 47 (b) 27 (c) 49
  29. 29.Which of these is a perfect cube? (a) 3477 (b) 3668 (c) 3375
  30. 30.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  31. 31.Which of these is a perfect cube? (a) 3232 (b) 2744 (c) 3066
  32. 32.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  33. 33.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  34. 34.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  35. 35.Which of these is a perfect cube? (a) 1164 (b) 1000 (c) 1088
  36. 36.Which of these is a perfect cube? (a) 556 (b) 512 (c) 664
  37. 37.What is 11³? =
  38. 38.What is ∛13824? =
  39. 39.Which of these is a perfect cube? (a) 1459 (b) 1331 (c) 1414
  40. 40.Which of these is a perfect cube? (a) 2484 (b) 2265 (c) 2197

Answer key

  1. 14
  2. 4
  3. 8
  4. 20
  5. 27
  6. 13
  7. 4913
  8. 17
  9. 21
  10. 5
  11. 216
  12. 3
  13. 729
  14. 15
  15. 7
  16. 4
  17. 343
  18. 15
  19. 125
  20. 216
  21. 12
  22. 12
  23. 2197
  24. 64
  25. 25
  26. 10
  27. 125
  28. 27
  29. 3375
  30. 11
  31. 2744
  32. 8
  33. 25
  34. 9
  35. 1000
  36. 512
  37. 1331
  38. 24
  39. 1331
  40. 2197

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