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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 858 · 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 14³? =
  2. 2.What is 6³? =
  3. 3.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  4. 4.What is ∛8? =
  5. 5.Which of these is a perfect cube? (a) 125 (b) 152 (c) 192
  6. 6.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  7. 7.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  8. 8.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  9. 9.What is 4³? =
  10. 10.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  11. 11.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  12. 12.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  13. 13.Which of these is a perfect cube? (a) 3508 (b) 3375 (c) 3471
  14. 14.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
  15. 15.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  16. 16.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  17. 17.Which of these is a perfect cube? (a) 2197 (b) 2223 (c) 2420
  18. 18.What is ∛1331? =
  19. 19.What is ∛15625? =
  20. 20.Which of these is a perfect cube? (a) 343 (b) 392 (c) 368
  21. 21.What is 11³? =
  22. 22.What is the smallest whole number by which 875 must be divided to get a perfect cube?
  23. 23.Which of these is a perfect cube? (a) 1924 (b) 1782 (c) 1728
  24. 24.What is ∛64? =
  25. 25.What is ∛1728? =
  26. 26.What is 18³? =
  27. 27.What is ∛3375? =
  28. 28.What is 15³? =
  29. 29.Which of these is a perfect cube? (a) 27 (b) 34 (c) 43
  30. 30.What is ∛4913? =
  31. 31.What is ∛125? =
  32. 32.What is 13³? =
  33. 33.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  34. 34.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  35. 35.What is ∛2197? =
  36. 36.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  37. 37.What is 9³? =
  38. 38.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  39. 39.What is ∛10648? =
  40. 40.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?

Answer key

  1. 2744
  2. 216
  3. 3
  4. 2
  5. 125
  6. 11
  7. 8
  8. 27
  9. 64
  10. 17
  11. 49
  12. 64
  13. 3375
  14. 49
  15. 18
  16. 125
  17. 2197
  18. 11
  19. 25
  20. 343
  21. 1331
  22. 7
  23. 1728
  24. 4
  25. 12
  26. 5832
  27. 15
  28. 3375
  29. 27
  30. 17
  31. 5
  32. 2197
  33. 5
  34. 20
  35. 13
  36. 3
  37. 729
  38. 216
  39. 22
  40. 9

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