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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 199 · 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 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  2. 2.What is 12³? =
  3. 3.What is 8³? =
  4. 4.What is 13³? =
  5. 5.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  6. 6.What is ∛3375? =
  7. 7.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  8. 8.What is ∛2744? =
  9. 9.What is 7³? =
  10. 10.Which of these is a perfect cube? (a) 2197 (b) 2276 (c) 2261
  11. 11.Which of these is a perfect cube? (a) 1273 (b) 1000 (c) 1063
  12. 12.What is 18³? =
  13. 13.What is ∛4913? =
  14. 14.What is ∛216? =
  15. 15.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  16. 16.What is ∛12167? =
  17. 17.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  18. 18.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
  19. 19.Which of these is a perfect cube? (a) 216 (b) 298 (c) 269
  20. 20.What is 19³? =
  21. 21.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  22. 22.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  23. 23.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  24. 24.Which of these is a perfect cube? (a) 105 (b) 64 (c) 77
  25. 25.What is ∛4096? =
  26. 26.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  27. 27.What is ∛9261? =
  28. 28.What is 2³? =
  29. 29.What is ∛125? =
  30. 30.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  31. 31.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  32. 32.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  33. 33.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  34. 34.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  35. 35.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  36. 36.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  37. 37.What is the smallest whole number by which 3125 must be divided to get a perfect cube?
  38. 38.Which of these is a perfect cube? (a) 512 (b) 587 (c) 585
  39. 39.Which of these is a perfect cube? (a) 1335 (b) 1505 (c) 1331
  40. 40.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?

Answer key

  1. 125
  2. 1728
  3. 512
  4. 2197
  5. 16
  6. 15
  7. 7
  8. 14
  9. 343
  10. 2197
  11. 1000
  12. 5832
  13. 17
  14. 6
  15. 7
  16. 23
  17. 49
  18. 49
  19. 216
  20. 6859
  21. 4
  22. 2
  23. 7
  24. 64
  25. 16
  26. 125
  27. 21
  28. 8
  29. 5
  30. 9
  31. 14
  32. 20
  33. 27
  34. 64
  35. 9
  36. 5
  37. 25
  38. 512
  39. 1331
  40. 216

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