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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 405 · 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 15³? =
  2. 2.What is 2³? =
  3. 3.What is 8³? =
  4. 4.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  5. 5.What is 9³? =
  6. 6.Which of these is a perfect cube? (a) 2462 (b) 2689 (c) 2197
  7. 7.What is ∛4913? =
  8. 8.What is ∛1728? =
  9. 9.What is ∛15625? =
  10. 10.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  11. 11.Which of these is a perfect cube? (a) 1481 (b) 1331 (c) 1350
  12. 12.What is ∛512? =
  13. 13.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  14. 14.What is 17³? =
  15. 15.What is 3³? =
  16. 16.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  17. 17.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  18. 18.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  19. 19.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  20. 20.What is ∛1331? =
  21. 21.Which of these is a perfect cube? (a) 125 (b) 172 (c) 183
  22. 22.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  23. 23.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  24. 24.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  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 ∛3375? =
  27. 27.Which of these is a perfect cube? (a) 104 (b) 86 (c) 64
  28. 28.What is ∛27? =
  29. 29.What is 6³? =
  30. 30.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  31. 31.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 343 (b) 368 (c) 460
  33. 33.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  34. 34.What is ∛1000? =
  35. 35.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  36. 36.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  37. 37.Which of these is a perfect cube? (a) 27 (b) 50 (c) 28
  38. 38.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  39. 39.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
  40. 40.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?

Answer key

  1. 3375
  2. 8
  3. 512
  4. 6
  5. 729
  6. 2197
  7. 17
  8. 12
  9. 25
  10. 216
  11. 1331
  12. 8
  13. 64
  14. 4913
  15. 27
  16. 5
  17. 4
  18. 19
  19. 3
  20. 11
  21. 125
  22. 216
  23. 125
  24. 9
  25. 8
  26. 15
  27. 64
  28. 3
  29. 216
  30. 7
  31. 27
  32. 343
  33. 14
  34. 10
  35. 49
  36. 27
  37. 27
  38. 216
  39. 49
  40. 5

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