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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 705 · 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 9³? =
  2. 2.Which of these is a perfect cube? (a) 1809 (b) 1728 (c) 2037
  3. 3.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  4. 4.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  5. 5.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
  6. 6.What is 20³? =
  7. 7.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  8. 8.What is the smallest whole number by which 256 must be divided to get a perfect cube?
  9. 9.What is ∛8000? =
  10. 10.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  11. 11.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  12. 12.Which of these is a perfect cube? (a) 1000 (b) 1016 (c) 1202
  13. 13.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  14. 14.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  15. 15.What is 13³? =
  16. 16.What is ∛27? =
  17. 17.What is ∛9261? =
  18. 18.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  19. 19.What is the smallest whole number by which 5 must be divided to get a perfect cube?
  20. 20.Which of these is a perfect cube? (a) 216 (b) 304 (c) 303
  21. 21.What is ∛512? =
  22. 22.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  23. 23.What is 2³? =
  24. 24.Which of these is a perfect cube? (a) 155 (b) 125 (c) 194
  25. 25.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  26. 26.What is the smallest whole number by which 25 must be divided to get a perfect cube?
  27. 27.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  28. 28.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  29. 29.What is 5³? =
  30. 30.What is 16³? =
  31. 31.What is ∛1331? =
  32. 32.What is ∛64? =
  33. 33.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  34. 34.What is ∛125? =
  35. 35.Which of these is a perfect cube? (a) 51 (b) 27 (c) 48
  36. 36.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  37. 37.What is 14³? =
  38. 38.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  39. 39.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  40. 40.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?

Answer key

  1. 729
  2. 1728
  3. 6
  4. 125
  5. 7
  6. 8000
  7. 8
  8. 4
  9. 20
  10. 14
  11. 7
  12. 1000
  13. 5
  14. 125
  15. 2197
  16. 3
  17. 21
  18. 2
  19. 5
  20. 216
  21. 8
  22. 27
  23. 8
  24. 125
  25. 216
  26. 25
  27. 216
  28. 7
  29. 125
  30. 4096
  31. 11
  32. 4
  33. 8
  34. 5
  35. 27
  36. 5
  37. 2744
  38. 27
  39. 18
  40. 125

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