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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 241 · 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 ∛10648? =
  2. 2.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  3. 3.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  4. 4.What is 14³? =
  5. 5.Which of these is a perfect cube? (a) 1629 (b) 1331 (c) 1336
  6. 6.What is 19³? =
  7. 7.Which of these is a perfect cube? (a) 314 (b) 246 (c) 216
  8. 8.Which of these is a perfect cube? (a) 3375 (b) 3632 (c) 3862
  9. 9.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  10. 10.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  11. 11.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  12. 12.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  13. 13.What is ∛2744? =
  14. 14.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  15. 15.Which of these is a perfect cube? (a) 520 (b) 662 (c) 512
  16. 16.What is 15³? =
  17. 17.What is 12³? =
  18. 18.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  19. 19.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  20. 20.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  21. 21.What is 16³? =
  22. 22.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  23. 23.What is ∛343? =
  24. 24.Which of these is a perfect cube? (a) 180 (b) 129 (c) 125
  25. 25.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  26. 26.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  27. 27.Which of these is a perfect cube? (a) 95 (b) 64 (c) 111
  28. 28.What is ∛5832? =
  29. 29.What is ∛8000? =
  30. 30.What is the smallest whole number by which 5400 must be divided to get a perfect cube?
  31. 31.Which of these is a perfect cube? (a) 27 (b) 45 (c) 40
  32. 32.What is ∛512? =
  33. 33.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  34. 34.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  35. 35.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  36. 36.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  37. 37.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  38. 38.What is ∛3375? =
  39. 39.What is ∛8? =
  40. 40.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?

Answer key

  1. 22
  2. 25
  3. 5
  4. 2744
  5. 1331
  6. 6859
  7. 216
  8. 3375
  9. 5
  10. 64
  11. 216
  12. 27
  13. 14
  14. 3
  15. 512
  16. 3375
  17. 1728
  18. 18
  19. 7
  20. 125
  21. 4096
  22. 10
  23. 7
  24. 125
  25. 19
  26. 8
  27. 64
  28. 18
  29. 20
  30. 25
  31. 27
  32. 8
  33. 8
  34. 25
  35. 11
  36. 16
  37. 6
  38. 15
  39. 2
  40. 2

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