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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 33 · 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 big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  2. 2.What is 8³? =
  3. 3.Which of these is a perfect cube? (a) 142 (b) 125 (c) 182
  4. 4.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  5. 5.What is 6³? =
  6. 6.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  7. 7.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  8. 8.What is ∛13824? =
  9. 9.Which of these is a perfect cube? (a) 1174 (b) 1160 (c) 1000
  10. 10.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  11. 11.What is ∛3375? =
  12. 12.Which of these is a perfect cube? (a) 2197 (b) 2690 (c) 2329
  13. 13.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  14. 14.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  15. 15.What is ∛27? =
  16. 16.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  17. 17.What is ∛15625? =
  18. 18.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  19. 19.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  20. 20.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  21. 21.What is 7³? =
  22. 22.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  23. 23.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  24. 24.Which of these is a perfect cube? (a) 552 (b) 599 (c) 512
  25. 25.What is 9³? =
  26. 26.Which of these is a perfect cube? (a) 33 (b) 54 (c) 27
  27. 27.What is 20³? =
  28. 28.Which of these is a perfect cube? (a) 4032 (b) 3375 (c) 3487
  29. 29.What is 16³? =
  30. 30.What is 14³? =
  31. 31.What is the smallest whole number by which 3125 must be divided to get a perfect cube?
  32. 32.What is 18³? =
  33. 33.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  34. 34.What is ∛8000? =
  35. 35.What is ∛1728? =
  36. 36.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  37. 37.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  38. 38.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  39. 39.What is ∛512? =
  40. 40.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?

Answer key

  1. 27
  2. 512
  3. 125
  4. 19
  5. 216
  6. 18
  7. 3
  8. 24
  9. 1000
  10. 2
  11. 15
  12. 2197
  13. 2
  14. 27
  15. 3
  16. 5
  17. 25
  18. 3
  19. 25
  20. 5
  21. 343
  22. 17
  23. 216
  24. 512
  25. 729
  26. 27
  27. 8000
  28. 3375
  29. 4096
  30. 2744
  31. 25
  32. 5832
  33. 10
  34. 20
  35. 12
  36. 8
  37. 16
  38. 216
  39. 8
  40. 8

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