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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 467 · 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 125 cubic cm. How long is each edge (in cm)?
  2. 2.Which of these is a perfect cube? (a) 79 (b) 64 (c) 112
  3. 3.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
  4. 4.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  5. 5.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  6. 6.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  7. 7.Which of these is a perfect cube? (a) 343 (b) 420 (c) 472
  8. 8.What is 7³? =
  9. 9.Which of these is a perfect cube? (a) 1879 (b) 1731 (c) 1728
  10. 10.What is the smallest whole number by which 25 must be divided to get a perfect cube?
  11. 11.Which of these is a perfect cube? (a) 2744 (b) 3021 (c) 3285
  12. 12.What is 6³? =
  13. 13.What is 11³? =
  14. 14.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  15. 15.What is ∛15625? =
  16. 16.What is ∛27? =
  17. 17.What is ∛343? =
  18. 18.What is 15³? =
  19. 19.What is 16³? =
  20. 20.What is 8³? =
  21. 21.What is ∛10648? =
  22. 22.What is ∛512? =
  23. 23.What is 12³? =
  24. 24.Which of these is a perfect cube? (a) 3709 (b) 3462 (c) 3375
  25. 25.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  26. 26.Which of these is a perfect cube? (a) 144 (b) 187 (c) 125
  27. 27.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  28. 28.Which of these is a perfect cube? (a) 934 (b) 729 (c) 908
  29. 29.What is 13³? =
  30. 30.What is 5³? =
  31. 31.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 216 (b) 291 (c) 303
  33. 33.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  34. 34.What is ∛125? =
  35. 35.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  36. 36.What is 14³? =
  37. 37.What is ∛2197? =
  38. 38.Which of these is a perfect cube? (a) 605 (b) 657 (c) 512
  39. 39.What is 19³? =
  40. 40.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?

Answer key

  1. 5
  2. 64
  3. 49
  4. 25
  5. 125
  6. 216
  7. 343
  8. 343
  9. 1728
  10. 25
  11. 2744
  12. 216
  13. 1331
  14. 2
  15. 25
  16. 3
  17. 7
  18. 3375
  19. 4096
  20. 512
  21. 22
  22. 8
  23. 1728
  24. 3375
  25. 64
  26. 125
  27. 3
  28. 729
  29. 2197
  30. 125
  31. 8
  32. 216
  33. 25
  34. 5
  35. 2
  36. 2744
  37. 13
  38. 512
  39. 6859
  40. 6

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