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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 344 · 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 ∛27? =
  2. 2.What is 5³? =
  3. 3.What is 20³? =
  4. 4.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  5. 5.What is 4³? =
  6. 6.Which of these is a perfect cube? (a) 1036 (b) 1054 (c) 1000
  7. 7.What is ∛1331? =
  8. 8.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  9. 9.What is 15³? =
  10. 10.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  11. 11.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
  12. 12.Which of these is a perfect cube? (a) 3907 (b) 3487 (c) 3375
  13. 13.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  14. 14.Which of these is a perfect cube? (a) 70 (b) 64 (c) 89
  15. 15.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  16. 16.Which of these is a perfect cube? (a) 1331 (b) 1415 (c) 1436
  17. 17.What is 19³? =
  18. 18.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  19. 19.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  20. 20.Which of these is a perfect cube? (a) 436 (b) 343 (c) 452
  21. 21.What is ∛10648? =
  22. 22.What is ∛12167? =
  23. 23.What is 7³? =
  24. 24.What is ∛4913? =
  25. 25.What is 13³? =
  26. 26.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  27. 27.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  28. 28.What is 10³? =
  29. 29.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  30. 30.What is ∛1728? =
  31. 31.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  32. 32.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  33. 33.Which of these is a perfect cube? (a) 222 (b) 271 (c) 216
  34. 34.What is 12³? =
  35. 35.What is 9³? =
  36. 36.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  37. 37.Which of these is a perfect cube? (a) 2246 (b) 2266 (c) 2197
  38. 38.What is ∛8? =
  39. 39.What is ∛125? =
  40. 40.What is 3³? =

Answer key

  1. 3
  2. 125
  3. 8000
  4. 27
  5. 64
  6. 1000
  7. 11
  8. 3
  9. 3375
  10. 125
  11. 7
  12. 3375
  13. 125
  14. 64
  15. 5
  16. 1331
  17. 6859
  18. 4
  19. 14
  20. 343
  21. 22
  22. 23
  23. 343
  24. 17
  25. 2197
  26. 2
  27. 3
  28. 1000
  29. 9
  30. 12
  31. 2
  32. 216
  33. 216
  34. 1728
  35. 729
  36. 9
  37. 2197
  38. 2
  39. 5
  40. 27

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