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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 839 · 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 216 cubic cm. How long is each edge (in cm)?
  2. 2.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  3. 3.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  4. 4.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  5. 5.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  6. 6.What is ∛2197? =
  7. 7.What is ∛9261? =
  8. 8.What is ∛12167? =
  9. 9.What is 14³? =
  10. 10.Which of these is a perfect cube? (a) 73 (b) 67 (c) 64
  11. 11.What is ∛1728? =
  12. 12.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  13. 13.What is ∛1331? =
  14. 14.What is 2³? =
  15. 15.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  16. 16.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  17. 17.Which of these is a perfect cube? (a) 486 (b) 343 (c) 437
  18. 18.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  19. 19.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  20. 20.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  21. 21.Which of these is a perfect cube? (a) 645 (b) 512 (c) 562
  22. 22.Which of these is a perfect cube? (a) 2294 (b) 2197 (c) 2420
  23. 23.What is ∛4096? =
  24. 24.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  25. 25.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  26. 26.What is ∛4913? =
  27. 27.What is ∛27? =
  28. 28.What is 9³? =
  29. 29.What is 7³? =
  30. 30.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  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.What is ∛5832? =
  33. 33.What is 16³? =
  34. 34.What is ∛64? =
  35. 35.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  36. 36.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  37. 37.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  38. 38.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  39. 39.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  40. 40.What is ∛3375? =

Answer key

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

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