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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 22 · 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 ∛8000? =
  2. 2.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  3. 3.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  4. 4.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  5. 5.What is 20³? =
  6. 6.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  7. 7.What is ∛27? =
  8. 8.What is 14³? =
  9. 9.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  10. 10.What is ∛512? =
  11. 11.What is ∛2197? =
  12. 12.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  13. 13.What is ∛13824? =
  14. 14.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  15. 15.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  16. 16.What is 6³? =
  17. 17.Which of these is a perfect cube? (a) 125 (b) 156 (c) 136
  18. 18.What is 12³? =
  19. 19.What is ∛125? =
  20. 20.What is ∛5832? =
  21. 21.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  22. 22.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  23. 23.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  24. 24.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  25. 25.What is 10³? =
  26. 26.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  27. 27.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  28. 28.Which of these is a perfect cube? (a) 512 (b) 648 (c) 664
  29. 29.What is 17³? =
  30. 30.Which of these is a perfect cube? (a) 77 (b) 64 (c) 67
  31. 31.Which of these is a perfect cube? (a) 27 (b) 47 (c) 35
  32. 32.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  33. 33.What is 2³? =
  34. 34.What is ∛8? =
  35. 35.What is ∛343? =
  36. 36.Which of these is a perfect cube? (a) 1647 (b) 1331 (c) 1536
  37. 37.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  38. 38.What is 15³? =
  39. 39.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  40. 40.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?

Answer key

  1. 20
  2. 49
  3. 19
  4. 4
  5. 8000
  6. 4
  7. 3
  8. 2744
  9. 27
  10. 8
  11. 13
  12. 12
  13. 24
  14. 8
  15. 125
  16. 216
  17. 125
  18. 1728
  19. 5
  20. 18
  21. 6
  22. 64
  23. 7
  24. 14
  25. 1000
  26. 2
  27. 9
  28. 512
  29. 4913
  30. 64
  31. 27
  32. 49
  33. 8
  34. 2
  35. 7
  36. 1331
  37. 216
  38. 3375
  39. 2
  40. 8

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