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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 299 · 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 17³? =
  2. 2.What is 19³? =
  3. 3.What is 7³? =
  4. 4.What is 5³? =
  5. 5.Which of these is a perfect cube? (a) 2744 (b) 3159 (c) 3331
  6. 6.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  7. 7.What is ∛343? =
  8. 8.Which of these is a perfect cube? (a) 2029 (b) 1728 (c) 1752
  9. 9.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  10. 10.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  11. 11.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  12. 12.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  13. 13.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  14. 14.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  15. 15.What is ∛3375? =
  16. 16.What is 2³? =
  17. 17.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  18. 18.What is 18³? =
  19. 19.What is ∛729? =
  20. 20.What is 4³? =
  21. 21.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  22. 22.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  23. 23.What is 13³? =
  24. 24.What is ∛2744? =
  25. 25.What is 15³? =
  26. 26.Which of these is a perfect cube? (a) 35 (b) 53 (c) 27
  27. 27.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  28. 28.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  29. 29.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  30. 30.What is 12³? =
  31. 31.Which of these is a perfect cube? (a) 383 (b) 464 (c) 343
  32. 32.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  33. 33.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  34. 34.What is ∛125? =
  35. 35.Which of these is a perfect cube? (a) 3375 (b) 3538 (c) 3786
  36. 36.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  37. 37.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  38. 38.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  39. 39.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  40. 40.What is ∛27? =

Answer key

  1. 4913
  2. 6859
  3. 343
  4. 125
  5. 2744
  6. 2
  7. 7
  8. 1728
  9. 7
  10. 13
  11. 12
  12. 8
  13. 6
  14. 5
  15. 15
  16. 8
  17. 27
  18. 5832
  19. 9
  20. 64
  21. 125
  22. 4
  23. 2197
  24. 14
  25. 3375
  26. 27
  27. 3
  28. 3
  29. 25
  30. 1728
  31. 343
  32. 14
  33. 5
  34. 5
  35. 3375
  36. 64
  37. 5
  38. 125
  39. 25
  40. 3

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