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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 747 · 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) 519 (b) 538 (c) 512
  2. 2.What is the smallest whole number by which 2 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 big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  5. 5.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  6. 6.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  7. 7.Which of these is a perfect cube? (a) 3154 (b) 2744 (c) 2921
  8. 8.What is ∛4913? =
  9. 9.Which of these is a perfect cube? (a) 793 (b) 729 (c) 762
  10. 10.What is 14³? =
  11. 11.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
  12. 12.What is 9³? =
  13. 13.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  14. 14.Which of these is a perfect cube? (a) 72 (b) 112 (c) 64
  15. 15.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  16. 16.What is ∛8000? =
  17. 17.What is ∛216? =
  18. 18.What is ∛15625? =
  19. 19.What is 16³? =
  20. 20.What is 19³? =
  21. 21.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  22. 22.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  23. 23.Which of these is a perfect cube? (a) 27 (b) 32 (c) 49
  24. 24.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  25. 25.What is ∛10648? =
  26. 26.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  27. 27.What is ∛8? =
  28. 28.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  29. 29.What is 11³? =
  30. 30.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  31. 31.What is 3³? =
  32. 32.What is 12³? =
  33. 33.Which of these is a perfect cube? (a) 171 (b) 125 (c) 166
  34. 34.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  35. 35.What is 6³? =
  36. 36.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  37. 37.What is ∛64? =
  38. 38.What is ∛2744? =
  39. 39.What is 20³? =
  40. 40.What is ∛343? =

Answer key

  1. 512
  2. 2
  3. 19
  4. 216
  5. 2
  6. 64
  7. 2744
  8. 17
  9. 729
  10. 2744
  11. 49
  12. 729
  13. 25
  14. 64
  15. 125
  16. 20
  17. 6
  18. 25
  19. 4096
  20. 6859
  21. 4
  22. 7
  23. 27
  24. 27
  25. 22
  26. 27
  27. 2
  28. 8
  29. 1331
  30. 8
  31. 27
  32. 1728
  33. 125
  34. 64
  35. 216
  36. 27
  37. 4
  38. 14
  39. 8000
  40. 7

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