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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 960 · 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) 1113 (b) 1013 (c) 1000
  2. 2.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  3. 3.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  4. 4.What is ∛343? =
  5. 5.What is ∛5832? =
  6. 6.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  7. 7.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  8. 8.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  9. 9.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  10. 10.What is 17³? =
  11. 11.What is 11³? =
  12. 12.What is 20³? =
  13. 13.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  14. 14.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  15. 15.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  16. 16.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  17. 17.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  18. 18.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  19. 19.What is the smallest whole number by which 1080 must be divided to get a perfect cube?
  20. 20.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  21. 21.What is ∛15625? =
  22. 22.Which of these is a perfect cube? (a) 252 (b) 283 (c) 216
  23. 23.What is 14³? =
  24. 24.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  25. 25.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
  26. 26.Which of these is a perfect cube? (a) 27 (b) 39 (c) 37
  27. 27.What is ∛125? =
  28. 28.What is ∛10648? =
  29. 29.What is ∛4913? =
  30. 30.Which of these is a perfect cube? (a) 1479 (b) 1531 (c) 1331
  31. 31.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  32. 32.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  33. 33.What is 3³? =
  34. 34.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  35. 35.What is 9³? =
  36. 36.Which of these is a perfect cube? (a) 523 (b) 596 (c) 512
  37. 37.What is ∛1728? =
  38. 38.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  39. 39.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  40. 40.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?

Answer key

  1. 1000
  2. 3
  3. 125
  4. 7
  5. 18
  6. 25
  7. 7
  8. 20
  9. 8
  10. 4913
  11. 1331
  12. 8000
  13. 4
  14. 8
  15. 4
  16. 27
  17. 6
  18. 27
  19. 5
  20. 3
  21. 25
  22. 216
  23. 2744
  24. 49
  25. 9
  26. 27
  27. 5
  28. 22
  29. 17
  30. 1331
  31. 11
  32. 19
  33. 27
  34. 49
  35. 729
  36. 512
  37. 12
  38. 5
  39. 64
  40. 2

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