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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 913 · 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 ∛512? =
  2. 2.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  3. 3.Which of these is a perfect cube? (a) 99 (b) 108 (c) 64
  4. 4.What is ∛2197? =
  5. 5.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  6. 6.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  7. 7.Which of these is a perfect cube? (a) 3524 (b) 3375 (c) 3420
  8. 8.Which of these is a perfect cube? (a) 3214 (b) 3118 (c) 2744
  9. 9.What is 3³? =
  10. 10.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  11. 11.What is ∛4913? =
  12. 12.Which of these is a perfect cube? (a) 602 (b) 512 (c) 588
  13. 13.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  14. 14.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  15. 15.What is 14³? =
  16. 16.Which of these is a perfect cube? (a) 252 (b) 216 (c) 250
  17. 17.What is ∛729? =
  18. 18.What is ∛2744? =
  19. 19.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  20. 20.What is 9³? =
  21. 21.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  22. 22.What is 5³? =
  23. 23.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  24. 24.What is 2³? =
  25. 25.What is 4³? =
  26. 26.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  27. 27.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
  28. 28.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  29. 29.What is ∛125? =
  30. 30.What is ∛15625? =
  31. 31.What is ∛27? =
  32. 32.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  33. 33.What is 20³? =
  34. 34.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  35. 35.What is ∛343? =
  36. 36.Which of these is a perfect cube? (a) 144 (b) 125 (c) 129
  37. 37.What is ∛9261? =
  38. 38.Which of these is a perfect cube? (a) 740 (b) 729 (c) 971
  39. 39.What is ∛8? =
  40. 40.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?

Answer key

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

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