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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 455 · 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 18³? =
  2. 2.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  3. 3.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  4. 4.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  5. 5.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  7. 7.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  8. 8.What is 12³? =
  9. 9.What is ∛1331? =
  10. 10.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  11. 11.What is ∛729? =
  12. 12.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  13. 13.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  14. 14.Which of these is a perfect cube? (a) 298 (b) 216 (c) 317
  15. 15.What is ∛2197? =
  16. 16.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  17. 17.What is ∛8000? =
  18. 18.What is ∛15625? =
  19. 19.Which of these is a perfect cube? (a) 2744 (b) 2935 (c) 2798
  20. 20.Which of these is a perfect cube? (a) 426 (b) 449 (c) 343
  21. 21.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  22. 22.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  23. 23.What is the smallest whole number by which 864 must be divided to get a perfect cube?
  24. 24.What is 9³? =
  25. 25.What is ∛3375? =
  26. 26.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  27. 27.What is the smallest whole number by which 200 must be divided to get a perfect cube?
  28. 28.What is 7³? =
  29. 29.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  30. 30.What is 10³? =
  31. 31.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  32. 32.What is 11³? =
  33. 33.What is ∛9261? =
  34. 34.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  35. 35.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  36. 36.What is 15³? =
  37. 37.Which of these is a perfect cube? (a) 29 (b) 27 (c) 48
  38. 38.Which of these is a perfect cube? (a) 151 (b) 125 (c) 144
  39. 39.What is 16³? =
  40. 40.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?

Answer key

  1. 5832
  2. 5
  3. 6
  4. 18
  5. 64
  6. 27
  7. 49
  8. 1728
  9. 11
  10. 5
  11. 9
  12. 3
  13. 27
  14. 216
  15. 13
  16. 125
  17. 20
  18. 25
  19. 2744
  20. 343
  21. 9
  22. 20
  23. 4
  24. 729
  25. 15
  26. 2
  27. 25
  28. 343
  29. 4
  30. 1000
  31. 125
  32. 1331
  33. 21
  34. 13
  35. 3
  36. 3375
  37. 27
  38. 125
  39. 4096
  40. 7

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