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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 309 · 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.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  2. 2.What is ∛125? =
  3. 3.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  4. 4.What is the smallest whole number by which 500 must be multiplied to get a perfect cube?
  5. 5.Which of these is a perfect cube? (a) 512 (b) 581 (c) 643
  6. 6.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  7. 7.What is 5³? =
  8. 8.What is 20³? =
  9. 9.What is 9³? =
  10. 10.Which of these is a perfect cube? (a) 2586 (b) 2242 (c) 2197
  11. 11.What is 6³? =
  12. 12.What is the smallest whole number by which 200 must be divided to get a perfect cube?
  13. 13.What is ∛729? =
  14. 14.What is ∛15625? =
  15. 15.What is ∛4913? =
  16. 16.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  17. 17.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  18. 18.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  19. 19.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  20. 20.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  21. 21.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  22. 22.What is ∛13824? =
  23. 23.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  24. 24.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  25. 25.What is 17³? =
  26. 26.Which of these is a perfect cube? (a) 108 (b) 80 (c) 64
  27. 27.What is 12³? =
  28. 28.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  29. 29.What is 11³? =
  30. 30.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  31. 31.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  32. 32.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  33. 33.Which of these is a perfect cube? (a) 154 (b) 125 (c) 129
  34. 34.What is ∛343? =
  35. 35.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  36. 36.What is ∛6859? =
  37. 37.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
  38. 38.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  39. 39.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  40. 40.What is 2³? =

Answer key

  1. 7
  2. 5
  3. 8
  4. 2
  5. 512
  6. 5
  7. 125
  8. 8000
  9. 729
  10. 2197
  11. 216
  12. 25
  13. 9
  14. 25
  15. 17
  16. 4
  17. 2
  18. 27
  19. 9
  20. 14
  21. 12
  22. 24
  23. 11
  24. 125
  25. 4913
  26. 64
  27. 1728
  28. 27
  29. 1331
  30. 6
  31. 7
  32. 17
  33. 125
  34. 7
  35. 2
  36. 19
  37. 9
  38. 25
  39. 15
  40. 8

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