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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 76 · 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 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  2. 2.Which of these is a perfect cube? (a) 735 (b) 888 (c) 729
  3. 3.What is ∛1728? =
  4. 4.Which of these is a perfect cube? (a) 2509 (b) 2227 (c) 2197
  5. 5.What is 17³? =
  6. 6.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  7. 7.What is 16³? =
  8. 8.What is 14³? =
  9. 9.What is 3³? =
  10. 10.What is ∛27? =
  11. 11.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  12. 12.What is 12³? =
  13. 13.What is ∛3375? =
  14. 14.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  15. 15.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  16. 16.What is ∛13824? =
  17. 17.What is ∛343? =
  18. 18.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  19. 19.Which of these is a perfect cube? (a) 1781 (b) 1961 (c) 1728
  20. 20.What is ∛4096? =
  21. 21.Which of these is a perfect cube? (a) 512 (b) 651 (c) 672
  22. 22.Which of these is a perfect cube? (a) 1331 (b) 1481 (c) 1621
  23. 23.What is 10³? =
  24. 24.What is ∛12167? =
  25. 25.Which of these is a perfect cube? (a) 3375 (b) 3548 (c) 3551
  26. 26.What is ∛729? =
  27. 27.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  28. 28.Which of these is a perfect cube? (a) 41 (b) 32 (c) 27
  29. 29.What is 5³? =
  30. 30.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  31. 31.What is 20³? =
  32. 32.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  33. 33.What is ∛64? =
  34. 34.What is ∛1000? =
  35. 35.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  36. 36.What is ∛512? =
  37. 37.Which of these is a perfect cube? (a) 1129 (b) 1000 (c) 1036
  38. 38.What is ∛2744? =
  39. 39.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  40. 40.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?

Answer key

  1. 8
  2. 729
  3. 12
  4. 2197
  5. 4913
  6. 3
  7. 4096
  8. 2744
  9. 27
  10. 3
  11. 125
  12. 1728
  13. 15
  14. 7
  15. 7
  16. 24
  17. 7
  18. 49
  19. 1728
  20. 16
  21. 512
  22. 1331
  23. 1000
  24. 23
  25. 3375
  26. 9
  27. 64
  28. 27
  29. 125
  30. 5
  31. 8000
  32. 6
  33. 4
  34. 10
  35. 64
  36. 8
  37. 1000
  38. 14
  39. 125
  40. 7

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