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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 53 · 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 ∛2744? =
  2. 2.What is 15³? =
  3. 3.What is ∛8000? =
  4. 4.What is ∛10648? =
  5. 5.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  6. 6.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  7. 7.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  8. 8.What is ∛8? =
  9. 9.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.What is ∛512? =
  11. 11.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  12. 12.What is ∛4913? =
  13. 13.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  14. 14.What is ∛2197? =
  15. 15.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  16. 16.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  17. 17.What is 14³? =
  18. 18.Which of these is a perfect cube? (a) 28 (b) 27 (c) 52
  19. 19.What is 20³? =
  20. 20.What is ∛1000? =
  21. 21.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
  22. 22.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  23. 23.What is ∛3375? =
  24. 24.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  25. 25.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  26. 26.What is ∛15625? =
  27. 27.Which of these is a perfect cube? (a) 653 (b) 567 (c) 512
  28. 28.Which of these is a perfect cube? (a) 275 (b) 216 (c) 283
  29. 29.Which of these is a perfect cube? (a) 798 (b) 919 (c) 729
  30. 30.What is ∛343? =
  31. 31.Which of these is a perfect cube? (a) 3375 (b) 3670 (c) 3453
  32. 32.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  33. 33.What is the smallest whole number by which 108 must be divided to get a perfect cube?
  34. 34.Which of these is a perfect cube? (a) 82 (b) 76 (c) 64
  35. 35.Which of these is a perfect cube? (a) 2068 (b) 1728 (c) 1963
  36. 36.What is 5³? =
  37. 37.What is ∛729? =
  38. 38.What is 8³? =
  39. 39.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  40. 40.What is the smallest whole number by which 72 must be multiplied to get a perfect cube?

Answer key

  1. 14
  2. 3375
  3. 20
  4. 22
  5. 14
  6. 25
  7. 216
  8. 2
  9. 125
  10. 8
  11. 8
  12. 17
  13. 27
  14. 13
  15. 13
  16. 7
  17. 2744
  18. 27
  19. 8000
  20. 10
  21. 49
  22. 49
  23. 15
  24. 125
  25. 8
  26. 25
  27. 512
  28. 216
  29. 729
  30. 7
  31. 3375
  32. 7
  33. 4
  34. 64
  35. 1728
  36. 125
  37. 9
  38. 512
  39. 8
  40. 3

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