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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 548 · 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 ∛10648? =
  2. 2.What is the smallest whole number by which 625 must be divided to get a perfect cube?
  3. 3.Which of these is a perfect cube? (a) 1731 (b) 1728 (c) 1907
  4. 4.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  5. 5.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.What is 10³? =
  7. 7.What is ∛13824? =
  8. 8.What is 5³? =
  9. 9.What is ∛4913? =
  10. 10.What is ∛1000? =
  11. 11.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  12. 12.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  13. 13.What is 9³? =
  14. 14.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  15. 15.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  16. 16.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  17. 17.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  18. 18.Which of these is a perfect cube? (a) 125 (b) 170 (c) 161
  19. 19.What is ∛216? =
  20. 20.What is 12³? =
  21. 21.What is 4³? =
  22. 22.What is ∛12167? =
  23. 23.What is the smallest whole number by which 24 must be divided to get a perfect cube?
  24. 24.What is ∛15625? =
  25. 25.Which of these is a perfect cube? (a) 3743 (b) 3854 (c) 3375
  26. 26.What is ∛125? =
  27. 27.What is ∛64? =
  28. 28.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  29. 29.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  30. 30.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  31. 31.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 51 (b) 27 (c) 45
  33. 33.What is 18³? =
  34. 34.What is ∛8? =
  35. 35.What is 17³? =
  36. 36.What is ∛1728? =
  37. 37.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  38. 38.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  39. 39.What is ∛2197? =
  40. 40.What is the smallest whole number by which 256 must be divided to get a perfect cube?

Answer key

  1. 22
  2. 5
  3. 1728
  4. 64
  5. 8
  6. 1000
  7. 24
  8. 125
  9. 17
  10. 10
  11. 64
  12. 5
  13. 729
  14. 7
  15. 216
  16. 18
  17. 49
  18. 125
  19. 6
  20. 1728
  21. 64
  22. 23
  23. 3
  24. 25
  25. 3375
  26. 5
  27. 4
  28. 10
  29. 13
  30. 6
  31. 27
  32. 27
  33. 5832
  34. 2
  35. 4913
  36. 12
  37. 25
  38. 216
  39. 13
  40. 4

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