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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 250 · 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 8³? =
  2. 2.What is 3³? =
  3. 3.What is 7³? =
  4. 4.What is ∛5832? =
  5. 5.What is ∛3375? =
  6. 6.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
  7. 7.What is ∛4096? =
  8. 8.What is 13³? =
  9. 9.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  10. 10.What is ∛8? =
  11. 11.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  12. 12.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  13. 13.Which of these is a perfect cube? (a) 1728 (b) 1883 (c) 1773
  14. 14.Which of these is a perfect cube? (a) 140 (b) 125 (c) 145
  15. 15.What is the smallest whole number by which 500 must be divided to get a perfect cube?
  16. 16.What is 20³? =
  17. 17.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  18. 18.Which of these is a perfect cube? (a) 1085 (b) 1000 (c) 1106
  19. 19.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?
  20. 20.What is the smallest whole number by which 72 must be multiplied to get a perfect cube?
  21. 21.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  22. 22.What is 10³? =
  23. 23.What is ∛27? =
  24. 24.What is 12³? =
  25. 25.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  26. 26.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  27. 27.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  28. 28.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  29. 29.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  30. 30.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  31. 31.What is the smallest whole number by which 625 must be divided to get a perfect cube?
  32. 32.What is ∛216? =
  33. 33.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  34. 34.Which of these is a perfect cube? (a) 2744 (b) 3307 (c) 2797
  35. 35.What is ∛512? =
  36. 36.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  37. 37.What is 15³? =
  38. 38.Which of these is a perfect cube? (a) 552 (b) 512 (c) 656
  39. 39.Which of these is a perfect cube? (a) 796 (b) 729 (c) 901
  40. 40.Which of these is a perfect cube? (a) 109 (b) 72 (c) 64

Answer key

  1. 512
  2. 27
  3. 343
  4. 18
  5. 15
  6. 9
  7. 16
  8. 2197
  9. 16
  10. 2
  11. 4
  12. 64
  13. 1728
  14. 125
  15. 4
  16. 8000
  17. 5
  18. 1000
  19. 7
  20. 3
  21. 5
  22. 1000
  23. 3
  24. 1728
  25. 4
  26. 2
  27. 3
  28. 9
  29. 2
  30. 20
  31. 5
  32. 6
  33. 2
  34. 2744
  35. 8
  36. 125
  37. 3375
  38. 512
  39. 729
  40. 64

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