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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 146 · 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.Which of these is a perfect cube? (a) 954 (b) 729 (c) 827
  2. 2.What is 16³? =
  3. 3.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  4. 4.Which of these is a perfect cube? (a) 1742 (b) 1728 (c) 1992
  5. 5.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  6. 6.Which of these is a perfect cube? (a) 3570 (b) 3375 (c) 3667
  7. 7.What is 12³? =
  8. 8.What is 15³? =
  9. 9.What is 11³? =
  10. 10.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  11. 11.What is ∛2744? =
  12. 12.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  13. 13.What is 20³? =
  14. 14.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  15. 15.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  16. 16.What is 4³? =
  17. 17.Which of these is a perfect cube? (a) 2539 (b) 2364 (c) 2197
  18. 18.What is the smallest whole number by which 25 must be divided to get a perfect cube?
  19. 19.What is 13³? =
  20. 20.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  21. 21.What is ∛8000? =
  22. 22.What is the smallest whole number by which 675 must be multiplied to get a perfect cube?
  23. 23.What is 5³? =
  24. 24.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  25. 25.What is ∛512? =
  26. 26.What is ∛8? =
  27. 27.Which of these is a perfect cube? (a) 110 (b) 71 (c) 64
  28. 28.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  29. 29.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  30. 30.What is 17³? =
  31. 31.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  32. 32.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  33. 33.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  34. 34.What is ∛729? =
  35. 35.What is the smallest whole number by which 81 must be divided to get a perfect cube?
  36. 36.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  37. 37.What is ∛3375? =
  38. 38.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  39. 39.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  40. 40.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?

Answer key

  1. 729
  2. 4096
  3. 5
  4. 1728
  5. 12
  6. 3375
  7. 1728
  8. 3375
  9. 1331
  10. 5
  11. 14
  12. 3
  13. 8000
  14. 216
  15. 2
  16. 64
  17. 2197
  18. 25
  19. 2197
  20. 27
  21. 20
  22. 5
  23. 125
  24. 25
  25. 8
  26. 2
  27. 64
  28. 17
  29. 216
  30. 4913
  31. 4
  32. 49
  33. 20
  34. 9
  35. 3
  36. 13
  37. 15
  38. 8
  39. 2
  40. 14

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