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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 413 · 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 ∛1331? =
  2. 2.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?
  3. 3.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  4. 4.Which of these is a perfect cube? (a) 293 (b) 216 (c) 280
  5. 5.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  6. 6.Which of these is a perfect cube? (a) 125 (b) 152 (c) 142
  7. 7.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  8. 8.What is 9³? =
  9. 9.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.Which of these is a perfect cube? (a) 3010 (b) 2744 (c) 3273
  11. 11.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  12. 12.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  13. 13.What is 2³? =
  14. 14.What is 3³? =
  15. 15.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  16. 16.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  17. 17.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  18. 18.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  19. 19.What is 17³? =
  20. 20.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  21. 21.What is ∛4096? =
  22. 22.What is 20³? =
  23. 23.What is 6³? =
  24. 24.What is ∛5832? =
  25. 25.What is ∛64? =
  26. 26.What is 13³? =
  27. 27.Which of these is a perfect cube? (a) 32 (b) 49 (c) 27
  28. 28.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  29. 29.Which of these is a perfect cube? (a) 2670 (b) 2485 (c) 2197
  30. 30.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  31. 31.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  32. 32.What is ∛216? =
  33. 33.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  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 the smallest whole number by which 24 must be divided to get a perfect cube?
  36. 36.What is ∛8? =
  37. 37.What is 14³? =
  38. 38.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  39. 39.What is ∛8000? =
  40. 40.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?

Answer key

  1. 11
  2. 7
  3. 4
  4. 216
  5. 8
  6. 125
  7. 16
  8. 729
  9. 125
  10. 2744
  11. 25
  12. 2
  13. 8
  14. 27
  15. 216
  16. 25
  17. 4
  18. 17
  19. 4913
  20. 216
  21. 16
  22. 8000
  23. 216
  24. 18
  25. 4
  26. 2197
  27. 27
  28. 2
  29. 2197
  30. 20
  31. 13
  32. 6
  33. 64
  34. 64
  35. 3
  36. 2
  37. 2744
  38. 216
  39. 20
  40. 8

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