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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 177 · 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 big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  2. 2.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  3. 3.What is 4³? =
  4. 4.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  5. 5.What is 20³? =
  6. 6.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  7. 7.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  8. 8.What is 2³? =
  9. 9.What is ∛13824? =
  10. 10.What is ∛8000? =
  11. 11.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
  12. 12.What is ∛2744? =
  13. 13.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  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) 1839 (b) 1728 (c) 2019
  16. 16.Which of these is a perfect cube? (a) 879 (b) 729 (c) 917
  17. 17.What is 7³? =
  18. 18.Which of these is a perfect cube? (a) 134 (b) 125 (c) 174
  19. 19.What is the smallest whole number by which 7 must be divided to get a perfect cube?
  20. 20.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  21. 21.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  22. 22.What is 15³? =
  23. 23.Which of these is a perfect cube? (a) 64 (b) 108 (c) 111
  24. 24.What is ∛9261? =
  25. 25.What is ∛4913? =
  26. 26.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  27. 27.What is 19³? =
  28. 28.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  29. 29.Which of these is a perfect cube? (a) 357 (b) 446 (c) 343
  30. 30.What is ∛1331? =
  31. 31.What is 3³? =
  32. 32.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  33. 33.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  34. 34.What is 18³? =
  35. 35.What is ∛3375? =
  36. 36.What is ∛5832? =
  37. 37.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  38. 38.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  39. 39.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  40. 40.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?

Answer key

  1. 8
  2. 4
  3. 64
  4. 125
  5. 8000
  6. 13
  7. 8
  8. 8
  9. 24
  10. 20
  11. 7
  12. 14
  13. 27
  14. 20
  15. 1728
  16. 729
  17. 343
  18. 125
  19. 7
  20. 5
  21. 9
  22. 3375
  23. 64
  24. 21
  25. 17
  26. 4
  27. 6859
  28. 9
  29. 343
  30. 11
  31. 27
  32. 3
  33. 3
  34. 5832
  35. 15
  36. 18
  37. 8
  38. 16
  39. 4
  40. 15

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