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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 26 · 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 cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  2. 2.What is ∛4913? =
  3. 3.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  4. 4.What is 18³? =
  5. 5.Which of these is a perfect cube? (a) 179 (b) 125 (c) 126
  6. 6.What is ∛125? =
  7. 7.Which of these is a perfect cube? (a) 3966 (b) 3375 (c) 3542
  8. 8.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  9. 9.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  10. 10.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  11. 11.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  12. 12.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  13. 13.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  14. 14.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  15. 15.Which of these is a perfect cube? (a) 101 (b) 111 (c) 64
  16. 16.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  17. 17.What is 20³? =
  18. 18.What is 9³? =
  19. 19.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  20. 20.Which of these is a perfect cube? (a) 400 (b) 435 (c) 343
  21. 21.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  22. 22.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  23. 23.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  24. 24.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  25. 25.Which of these is a perfect cube? (a) 2744 (b) 2925 (c) 2797
  26. 26.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
  27. 27.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  28. 28.What is ∛512? =
  29. 29.What is 4³? =
  30. 30.What is ∛27? =
  31. 31.What is ∛8? =
  32. 32.What is ∛1331? =
  33. 33.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  34. 34.What is ∛12167? =
  35. 35.Which of these is a perfect cube? (a) 950 (b) 828 (c) 729
  36. 36.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  37. 37.What is 7³? =
  38. 38.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  39. 39.What is 12³? =
  40. 40.What is 14³? =

Answer key

  1. 18
  2. 17
  3. 4
  4. 5832
  5. 125
  6. 5
  7. 3375
  8. 9
  9. 8
  10. 17
  11. 19
  12. 3
  13. 4
  14. 13
  15. 64
  16. 4
  17. 8000
  18. 729
  19. 2
  20. 343
  21. 125
  22. 125
  23. 3
  24. 9
  25. 2744
  26. 49
  27. 8
  28. 8
  29. 64
  30. 3
  31. 2
  32. 11
  33. 27
  34. 23
  35. 729
  36. 5
  37. 343
  38. 8
  39. 1728
  40. 2744

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