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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 601 · 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 4913 cubic cm. How long is each edge (in cm)?
  2. 2.What is ∛1331? =
  3. 3.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  4. 4.Which of these is a perfect cube? (a) 2793 (b) 2744 (c) 2869
  5. 5.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  6. 6.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  7. 7.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  8. 8.What is 6³? =
  9. 9.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  11. 11.What is 18³? =
  12. 12.What is ∛13824? =
  13. 13.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  14. 14.What is 20³? =
  15. 15.What is 12³? =
  16. 16.What is ∛1728? =
  17. 17.What is ∛15625? =
  18. 18.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  19. 19.What is 14³? =
  20. 20.What is ∛27? =
  21. 21.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  22. 22.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  23. 23.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  24. 24.What is ∛125? =
  25. 25.What is the smallest whole number by which 500 must be divided to get a perfect cube?
  26. 26.Which of these is a perfect cube? (a) 108 (b) 96 (c) 64
  27. 27.What is 3³? =
  28. 28.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  29. 29.What is the smallest whole number by which 24 must be divided to get a perfect cube?
  30. 30.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  31. 31.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  32. 32.What is ∛8? =
  33. 33.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  34. 34.What is ∛12167? =
  35. 35.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  36. 36.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  37. 37.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  38. 38.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  39. 39.What is ∛4913? =
  40. 40.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?

Answer key

  1. 17
  2. 11
  3. 125
  4. 2744
  5. 9
  6. 2
  7. 4
  8. 216
  9. 125
  10. 125
  11. 5832
  12. 24
  13. 64
  14. 8000
  15. 1728
  16. 12
  17. 25
  18. 11
  19. 2744
  20. 3
  21. 2
  22. 19
  23. 5
  24. 5
  25. 4
  26. 64
  27. 27
  28. 3
  29. 3
  30. 7
  31. 25
  32. 2
  33. 4
  34. 23
  35. 9
  36. 7
  37. 6
  38. 7
  39. 17
  40. 27

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