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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 581 · 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 ∛4913? =
  2. 2.Which of these is a perfect cube? (a) 529 (b) 515 (c) 512
  3. 3.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  4. 4.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  5. 5.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  6. 6.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  7. 7.What is the smallest whole number by which 1080 must be divided to get a perfect cube?
  8. 8.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  9. 9.What is 7³? =
  10. 10.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  11. 11.What is 8³? =
  12. 12.What is ∛5832? =
  13. 13.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  14. 14.What is ∛1728? =
  15. 15.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
  16. 16.Which of these is a perfect cube? (a) 27 (b) 47 (c) 46
  17. 17.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  18. 18.What is ∛27? =
  19. 19.What is ∛8000? =
  20. 20.What is ∛13824? =
  21. 21.What is ∛1000? =
  22. 22.What is ∛2744? =
  23. 23.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  24. 24.What is 18³? =
  25. 25.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  26. 26.What is 9³? =
  27. 27.Which of these is a perfect cube? (a) 234 (b) 253 (c) 216
  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 375 must be multiplied to get a perfect cube?
  30. 30.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  31. 31.What is ∛729? =
  32. 32.What is 12³? =
  33. 33.Which of these is a perfect cube? (a) 64 (b) 109 (c) 108
  34. 34.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  35. 35.What is ∛6859? =
  36. 36.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  37. 37.Which of these is a perfect cube? (a) 146 (b) 177 (c) 125
  38. 38.What is 3³? =
  39. 39.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  40. 40.Which of these is a perfect cube? (a) 1331 (b) 1459 (c) 1663

Answer key

  1. 17
  2. 512
  3. 3
  4. 4
  5. 5
  6. 4
  7. 5
  8. 7
  9. 343
  10. 216
  11. 512
  12. 18
  13. 15
  14. 12
  15. 9
  16. 27
  17. 11
  18. 3
  19. 20
  20. 24
  21. 10
  22. 14
  23. 5
  24. 5832
  25. 8
  26. 729
  27. 216
  28. 3
  29. 9
  30. 6
  31. 9
  32. 1728
  33. 64
  34. 125
  35. 19
  36. 64
  37. 125
  38. 27
  39. 8
  40. 1331

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