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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 997 · 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 ∛64? =
  3. 3.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  4. 4.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  5. 5.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  6. 6.Which of these is a perfect cube? (a) 2280 (b) 2678 (c) 2197
  7. 7.What is 18³? =
  8. 8.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛2197? =
  10. 10.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  11. 11.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  12. 12.What is the smallest whole number by which 675 must be divided to get a perfect cube?
  13. 13.What is ∛512? =
  14. 14.Which of these is a perfect cube? (a) 179 (b) 145 (c) 125
  15. 15.What is ∛12167? =
  16. 16.Which of these is a perfect cube? (a) 1728 (b) 1766 (c) 1904
  17. 17.What is 19³? =
  18. 18.What is 10³? =
  19. 19.What is ∛9261? =
  20. 20.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  21. 21.What is 3³? =
  22. 22.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  23. 23.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  24. 24.What is ∛15625? =
  25. 25.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
  26. 26.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  27. 27.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  28. 28.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  29. 29.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  30. 30.What is the smallest whole number by which 1512 must be divided to get a perfect cube?
  31. 31.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  32. 32.What is 11³? =
  33. 33.Which of these is a perfect cube? (a) 455 (b) 357 (c) 343
  34. 34.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  35. 35.What is 15³? =
  36. 36.Which of these is a perfect cube? (a) 44 (b) 27 (c) 53
  37. 37.Which of these is a perfect cube? (a) 3564 (b) 3375 (c) 3399
  38. 38.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  39. 39.What is 7³? =
  40. 40.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?

Answer key

  1. 14
  2. 4
  3. 7
  4. 27
  5. 49
  6. 2197
  7. 5832
  8. 3
  9. 13
  10. 15
  11. 4
  12. 25
  13. 8
  14. 125
  15. 23
  16. 1728
  17. 6859
  18. 1000
  19. 21
  20. 8
  21. 27
  22. 10
  23. 4
  24. 25
  25. 49
  26. 19
  27. 14
  28. 9
  29. 2
  30. 7
  31. 8
  32. 1331
  33. 343
  34. 2
  35. 3375
  36. 27
  37. 3375
  38. 11
  39. 343
  40. 25

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