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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 863 · 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 ∛3375? =
  2. 2.Which of these is a perfect cube? (a) 649 (b) 512 (c) 634
  3. 3.What is 4³? =
  4. 4.What is 14³? =
  5. 5.What is ∛729? =
  6. 6.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  7. 7.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  8. 8.What is ∛1331? =
  9. 9.What is 2³? =
  10. 10.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  11. 11.What is ∛64? =
  12. 12.Which of these is a perfect cube? (a) 3653 (b) 3375 (c) 3689
  13. 13.What is ∛343? =
  14. 14.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  15. 15.What is ∛512? =
  16. 16.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  17. 17.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  18. 18.What is the smallest whole number by which 1512 must be divided to get a perfect cube?
  19. 19.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  20. 20.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  21. 21.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  22. 22.Which of these is a perfect cube? (a) 1817 (b) 1728 (c) 1962
  23. 23.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  24. 24.What is ∛1728? =
  25. 25.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  26. 26.Which of these is a perfect cube? (a) 485 (b) 343 (c) 400
  27. 27.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  28. 28.Which of these is a perfect cube? (a) 34 (b) 53 (c) 27
  29. 29.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  30. 30.What is ∛8000? =
  31. 31.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  32. 32.Which of these is a perfect cube? (a) 216 (b) 227 (c) 251
  33. 33.What is 15³? =
  34. 34.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  35. 35.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  36. 36.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  37. 37.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  38. 38.Which of these is a perfect cube? (a) 809 (b) 729 (c) 757
  39. 39.What is ∛2197? =
  40. 40.What is 11³? =

Answer key

  1. 15
  2. 512
  3. 64
  4. 2744
  5. 9
  6. 8
  7. 5
  8. 11
  9. 8
  10. 8
  11. 4
  12. 3375
  13. 7
  14. 19
  15. 8
  16. 20
  17. 9
  18. 7
  19. 2
  20. 64
  21. 27
  22. 1728
  23. 27
  24. 12
  25. 216
  26. 343
  27. 10
  28. 27
  29. 7
  30. 20
  31. 6
  32. 216
  33. 3375
  34. 11
  35. 18
  36. 15
  37. 7
  38. 729
  39. 13
  40. 1331

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