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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 13 · 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 ∛13824? =
  2. 2.Which of these is a perfect cube? (a) 64 (b) 111 (c) 69
  3. 3.What is 9³? =
  4. 4.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  5. 5.What is ∛729? =
  6. 6.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  7. 7.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  8. 8.Which of these is a perfect cube? (a) 4048 (b) 3729 (c) 3375
  9. 9.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  11. 11.What is 13³? =
  12. 12.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  13. 13.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  14. 14.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  15. 15.Which of these is a perfect cube? (a) 2197 (b) 2285 (c) 2418
  16. 16.Which of these is a perfect cube? (a) 125 (b) 151 (c) 161
  17. 17.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  18. 18.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  19. 19.What is 17³? =
  20. 20.What is 15³? =
  21. 21.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  22. 22.What is ∛1000? =
  23. 23.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  24. 24.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  25. 25.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  26. 26.What is ∛216? =
  27. 27.What is 3³? =
  28. 28.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  29. 29.Which of these is a perfect cube? (a) 729 (b) 868 (c) 857
  30. 30.What is 7³? =
  31. 31.What is ∛2744? =
  32. 32.What is ∛4913? =
  33. 33.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  34. 34.Which of these is a perfect cube? (a) 3228 (b) 2968 (c) 2744
  35. 35.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  36. 36.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  37. 37.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  38. 38.What is 20³? =
  39. 39.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  40. 40.What is 8³? =

Answer key

  1. 24
  2. 64
  3. 729
  4. 6
  5. 9
  6. 5
  7. 3
  8. 3375
  9. 64
  10. 125
  11. 2197
  12. 49
  13. 9
  14. 20
  15. 2197
  16. 125
  17. 17
  18. 7
  19. 4913
  20. 3375
  21. 18
  22. 10
  23. 7
  24. 8
  25. 49
  26. 6
  27. 27
  28. 16
  29. 729
  30. 343
  31. 14
  32. 17
  33. 64
  34. 2744
  35. 4
  36. 4
  37. 25
  38. 8000
  39. 8
  40. 512

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