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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 218 · 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 big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  2. 2.What is 4³? =
  3. 3.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  4. 4.What is the smallest whole number by which 200 must be divided to get a perfect cube?
  5. 5.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  6. 6.What is ∛4913? =
  7. 7.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  8. 8.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  9. 9.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  10. 10.What is 15³? =
  11. 11.Which of these is a perfect cube? (a) 583 (b) 512 (c) 606
  12. 12.What is ∛15625? =
  13. 13.What is 16³? =
  14. 14.What is ∛343? =
  15. 15.What is ∛64? =
  16. 16.Which of these is a perfect cube? (a) 1331 (b) 1531 (c) 1461
  17. 17.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  18. 18.What is 5³? =
  19. 19.What is ∛2744? =
  20. 20.Which of these is a perfect cube? (a) 2283 (b) 2342 (c) 2197
  21. 21.Which of these is a perfect cube? (a) 216 (b) 314 (c) 292
  22. 22.What is 12³? =
  23. 23.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  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.Which of these is a perfect cube? (a) 3714 (b) 3375 (c) 3875
  26. 26.What is 20³? =
  27. 27.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  28. 28.What is ∛1728? =
  29. 29.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  30. 30.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  31. 31.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  32. 32.Which of these is a perfect cube? (a) 1151 (b) 1000 (c) 1273
  33. 33.What is 6³? =
  34. 34.What is ∛729? =
  35. 35.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  36. 36.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  37. 37.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  38. 38.What is 17³? =
  39. 39.What is ∛1331? =
  40. 40.What is 2³? =

Answer key

  1. 64
  2. 64
  3. 7
  4. 25
  5. 19
  6. 17
  7. 4
  8. 216
  9. 8
  10. 3375
  11. 512
  12. 25
  13. 4096
  14. 7
  15. 4
  16. 1331
  17. 6
  18. 125
  19. 14
  20. 2197
  21. 216
  22. 1728
  23. 8
  24. 64
  25. 3375
  26. 8000
  27. 5
  28. 12
  29. 3
  30. 25
  31. 2
  32. 1000
  33. 216
  34. 9
  35. 4
  36. 10
  37. 3
  38. 4913
  39. 11
  40. 8

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