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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 197 · 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.Which of these is a perfect cube? (a) 216 (b) 280 (c) 247
  2. 2.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  3. 3.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  4. 4.What is the smallest whole number by which 875 must be divided to get a perfect cube?
  5. 5.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  6. 6.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  7. 7.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  8. 8.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛3375? =
  10. 10.Which of these is a perfect cube? (a) 921 (b) 729 (c) 925
  11. 11.What is ∛4096? =
  12. 12.What is ∛1331? =
  13. 13.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  14. 14.Which of these is a perfect cube? (a) 512 (b) 527 (c) 698
  15. 15.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  16. 16.What is ∛27? =
  17. 17.What is 12³? =
  18. 18.What is 11³? =
  19. 19.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  20. 20.Which of these is a perfect cube? (a) 3375 (b) 3910 (c) 3552
  21. 21.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  22. 22.What is 13³? =
  23. 23.What is 5³? =
  24. 24.What is 17³? =
  25. 25.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  26. 26.Which of these is a perfect cube? (a) 3060 (b) 2805 (c) 2744
  27. 27.What is 9³? =
  28. 28.What is 20³? =
  29. 29.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
  30. 30.Which of these is a perfect cube? (a) 1199 (b) 1183 (c) 1000
  31. 31.What is ∛1728? =
  32. 32.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  33. 33.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  34. 34.What is ∛64? =
  35. 35.Which of these is a perfect cube? (a) 405 (b) 464 (c) 343
  36. 36.What is ∛5832? =
  37. 37.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  38. 38.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  39. 39.Which of these is a perfect cube? (a) 175 (b) 176 (c) 125
  40. 40.What is ∛343? =

Answer key

  1. 216
  2. 15
  3. 4
  4. 7
  5. 2
  6. 8
  7. 7
  8. 3
  9. 15
  10. 729
  11. 16
  12. 11
  13. 17
  14. 512
  15. 125
  16. 3
  17. 1728
  18. 1331
  19. 9
  20. 3375
  21. 27
  22. 2197
  23. 125
  24. 4913
  25. 27
  26. 2744
  27. 729
  28. 8000
  29. 49
  30. 1000
  31. 12
  32. 16
  33. 125
  34. 4
  35. 343
  36. 18
  37. 20
  38. 5
  39. 125
  40. 7

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