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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 480 · 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 the smallest whole number by which 56 must be divided to get a perfect cube?
  2. 2.Which of these is a perfect cube? (a) 216 (b) 309 (c) 279
  3. 3.What is ∛729? =
  4. 4.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  5. 5.What is ∛27? =
  6. 6.What is 6³? =
  7. 7.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  8. 8.Which of these is a perfect cube? (a) 1331 (b) 1521 (c) 1338
  9. 9.What is ∛13824? =
  10. 10.What is ∛2197? =
  11. 11.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  12. 12.What is ∛4913? =
  13. 13.What is ∛216? =
  14. 14.What is ∛1331? =
  15. 15.What is ∛1728? =
  16. 16.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  17. 17.What is 4³? =
  18. 18.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  19. 19.What is ∛5832? =
  20. 20.What is 7³? =
  21. 21.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  22. 22.What is 10³? =
  23. 23.What is 2³? =
  24. 24.What is ∛3375? =
  25. 25.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  26. 26.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  27. 27.What is the smallest whole number by which 250 must be divided to get a perfect cube?
  28. 28.Which of these is a perfect cube? (a) 1728 (b) 1852 (c) 1812
  29. 29.What is the smallest whole number by which 1512 must be divided to get a perfect cube?
  30. 30.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  31. 31.What is 11³? =
  32. 32.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  33. 33.What is ∛8000? =
  34. 34.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  35. 35.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  36. 36.Which of these is a perfect cube? (a) 2454 (b) 2197 (c) 2387
  37. 37.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  38. 38.What is ∛4096? =
  39. 39.What is ∛8? =
  40. 40.What is ∛12167? =

Answer key

  1. 7
  2. 216
  3. 9
  4. 64
  5. 3
  6. 216
  7. 27
  8. 1331
  9. 24
  10. 13
  11. 64
  12. 17
  13. 6
  14. 11
  15. 12
  16. 27
  17. 64
  18. 20
  19. 18
  20. 343
  21. 8
  22. 1000
  23. 8
  24. 15
  25. 12
  26. 3
  27. 2
  28. 1728
  29. 7
  30. 4
  31. 1331
  32. 4
  33. 20
  34. 5
  35. 8
  36. 2197
  37. 125
  38. 16
  39. 2
  40. 23

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