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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 225 · 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 12³? =
  2. 2.Which of these is a perfect cube? (a) 2248 (b) 2197 (c) 2296
  3. 3.What is 19³? =
  4. 4.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  5. 5.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  6. 6.What is ∛343? =
  7. 7.What is ∛13824? =
  8. 8.Which of these is a perfect cube? (a) 2744 (b) 3162 (c) 3170
  9. 9.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  10. 10.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  11. 11.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  12. 12.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  13. 13.What is 4³? =
  14. 14.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  15. 15.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  16. 16.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  17. 17.What is ∛4096? =
  18. 18.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  19. 19.What is 5³? =
  20. 20.What is ∛64? =
  21. 21.What is ∛125? =
  22. 22.What is 11³? =
  23. 23.Which of these is a perfect cube? (a) 863 (b) 729 (c) 849
  24. 24.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  25. 25.What is the smallest whole number by which 864 must be divided to get a perfect cube?
  26. 26.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  27. 27.Which of these is a perfect cube? (a) 403 (b) 408 (c) 343
  28. 28.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  29. 29.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  30. 30.Which of these is a perfect cube? (a) 71 (b) 64 (c) 81
  31. 31.What is 20³? =
  32. 32.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  33. 33.What is 13³? =
  34. 34.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  35. 35.What is ∛216? =
  36. 36.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  37. 37.What is ∛10648? =
  38. 38.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  39. 39.What is 3³? =
  40. 40.What is the smallest whole number by which 200 must be divided to get a perfect cube?

Answer key

  1. 1728
  2. 2197
  3. 6859
  4. 6
  5. 20
  6. 7
  7. 24
  8. 2744
  9. 11
  10. 8
  11. 4
  12. 216
  13. 64
  14. 5
  15. 15
  16. 49
  17. 16
  18. 27
  19. 125
  20. 4
  21. 5
  22. 1331
  23. 729
  24. 64
  25. 4
  26. 2
  27. 343
  28. 8
  29. 7
  30. 64
  31. 8000
  32. 216
  33. 2197
  34. 216
  35. 6
  36. 9
  37. 22
  38. 10
  39. 27
  40. 25

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