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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 505 · 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 the smallest whole number by which 72 must be divided to get a perfect cube?
  2. 2.What is 3³? =
  3. 3.What is 5³? =
  4. 4.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  5. 5.What is ∛13824? =
  6. 6.What is ∛5832? =
  7. 7.Which of these is a perfect cube? (a) 1331 (b) 1460 (c) 1384
  8. 8.What is ∛2744? =
  9. 9.What is ∛729? =
  10. 10.What is ∛64? =
  11. 11.What is ∛8? =
  12. 12.Which of these is a perfect cube? (a) 191 (b) 128 (c) 125
  13. 13.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  14. 14.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  15. 15.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  16. 16.What is ∛216? =
  17. 17.What is the smallest whole number by which 7 must be divided to get a perfect cube?
  18. 18.What is 17³? =
  19. 19.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  20. 20.Which of these is a perfect cube? (a) 2426 (b) 2197 (c) 2351
  21. 21.What is 8³? =
  22. 22.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  23. 23.What is ∛2197? =
  24. 24.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  25. 25.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  26. 26.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  27. 27.What is ∛4913? =
  28. 28.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  29. 29.What is 20³? =
  30. 30.What is 6³? =
  31. 31.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 567 (b) 669 (c) 512
  33. 33.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  34. 34.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  35. 35.What is 4³? =
  36. 36.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  37. 37.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  38. 38.What is 18³? =
  39. 39.Which of these is a perfect cube? (a) 31 (b) 54 (c) 27
  40. 40.What is the smallest whole number by which 243 must be multiplied to get a perfect cube?

Answer key

  1. 9
  2. 27
  3. 125
  4. 3
  5. 24
  6. 18
  7. 1331
  8. 14
  9. 9
  10. 4
  11. 2
  12. 125
  13. 18
  14. 8
  15. 14
  16. 6
  17. 7
  18. 4913
  19. 2
  20. 2197
  21. 512
  22. 4
  23. 13
  24. 64
  25. 27
  26. 5
  27. 17
  28. 64
  29. 8000
  30. 216
  31. 216
  32. 512
  33. 11
  34. 5
  35. 64
  36. 9
  37. 17
  38. 5832
  39. 27
  40. 3

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