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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 768 · 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 729 cubic cm. How long is each edge (in cm)?
  2. 2.What is ∛5832? =
  3. 3.What is ∛9261? =
  4. 4.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  5. 5.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  6. 6.Which of these is a perfect cube? (a) 64 (b) 107 (c) 82
  7. 7.What is ∛1728? =
  8. 8.What is the smallest whole number by which 675 must be multiplied to get a perfect cube?
  9. 9.What is the smallest whole number by which 72 must be divided to get a perfect cube?
  10. 10.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  11. 11.What is ∛4096? =
  12. 12.What is ∛216? =
  13. 13.Which of these is a perfect cube? (a) 242 (b) 216 (c) 269
  14. 14.What is ∛27? =
  15. 15.What is 17³? =
  16. 16.Which of these is a perfect cube? (a) 46 (b) 27 (c) 47
  17. 17.What is 9³? =
  18. 18.Which of these is a perfect cube? (a) 3941 (b) 3375 (c) 3725
  19. 19.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  20. 20.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  21. 21.What is the smallest whole number by which 675 must be divided to get a perfect cube?
  22. 22.What is ∛8000? =
  23. 23.What is 10³? =
  24. 24.Which of these is a perfect cube? (a) 450 (b) 432 (c) 343
  25. 25.What is ∛125? =
  26. 26.What is 19³? =
  27. 27.Which of these is a perfect cube? (a) 512 (b) 589 (c) 525
  28. 28.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  29. 29.What is ∛13824? =
  30. 30.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  31. 31.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  32. 32.Which of these is a perfect cube? (a) 1654 (b) 1331 (c) 1389
  33. 33.What is 4³? =
  34. 34.What is 6³? =
  35. 35.What is ∛512? =
  36. 36.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  37. 37.What is ∛4913? =
  38. 38.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  39. 39.Which of these is a perfect cube? (a) 2197 (b) 2278 (c) 2585
  40. 40.What is ∛343? =

Answer key

  1. 9
  2. 18
  3. 21
  4. 3
  5. 10
  6. 64
  7. 12
  8. 5
  9. 9
  10. 8
  11. 16
  12. 6
  13. 216
  14. 3
  15. 4913
  16. 27
  17. 729
  18. 3375
  19. 5
  20. 25
  21. 25
  22. 20
  23. 1000
  24. 343
  25. 5
  26. 6859
  27. 512
  28. 18
  29. 24
  30. 216
  31. 2
  32. 1331
  33. 64
  34. 216
  35. 8
  36. 5
  37. 17
  38. 216
  39. 2197
  40. 7

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