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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 869 · 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 19³? =
  2. 2.Which of these is a perfect cube? (a) 1629 (b) 1331 (c) 1659
  3. 3.What is 9³? =
  4. 4.What is ∛125? =
  5. 5.What is 10³? =
  6. 6.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  7. 7.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  8. 8.What is 2³? =
  9. 9.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  10. 10.What is ∛64? =
  11. 11.What is 3³? =
  12. 12.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  13. 13.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  14. 14.What is ∛10648? =
  15. 15.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  16. 16.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  17. 17.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  18. 18.What is 18³? =
  19. 19.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  20. 20.What is ∛5832? =
  21. 21.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  22. 22.Which of these is a perfect cube? (a) 38 (b) 27 (c) 36
  23. 23.What is the smallest whole number by which 256 must be divided to get a perfect cube?
  24. 24.Which of these is a perfect cube? (a) 899 (b) 750 (c) 729
  25. 25.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  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.What is ∛1331? =
  28. 28.Which of these is a perfect cube? (a) 64 (b) 82 (c) 72
  29. 29.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  30. 30.Which of these is a perfect cube? (a) 1728 (b) 1877 (c) 1824
  31. 31.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  32. 32.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  33. 33.What is the smallest whole number by which 72 must be divided to get a perfect cube?
  34. 34.What is ∛9261? =
  35. 35.What is ∛3375? =
  36. 36.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  37. 37.What is ∛12167? =
  38. 38.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  39. 39.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  40. 40.Which of these is a perfect cube? (a) 148 (b) 125 (c) 166

Answer key

  1. 6859
  2. 1331
  3. 729
  4. 5
  5. 1000
  6. 20
  7. 8
  8. 8
  9. 64
  10. 4
  11. 27
  12. 19
  13. 8
  14. 22
  15. 5
  16. 15
  17. 27
  18. 5832
  19. 27
  20. 18
  21. 16
  22. 27
  23. 4
  24. 729
  25. 3
  26. 8
  27. 11
  28. 64
  29. 10
  30. 1728
  31. 5
  32. 2
  33. 9
  34. 21
  35. 15
  36. 17
  37. 23
  38. 3
  39. 12
  40. 125

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