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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 383 · 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 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  2. 2.What is 14³? =
  3. 3.Which of these is a perfect cube? (a) 529 (b) 512 (c) 554
  4. 4.What is ∛4913? =
  5. 5.What is 6³? =
  6. 6.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  7. 7.What is the smallest whole number by which 243 must be multiplied to get a perfect cube?
  8. 8.What is 4³? =
  9. 9.What is ∛8000? =
  10. 10.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  11. 11.What is ∛6859? =
  12. 12.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  13. 13.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  14. 14.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  15. 15.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
  16. 16.Which of these is a perfect cube? (a) 98 (b) 93 (c) 64
  17. 17.Which of these is a perfect cube? (a) 2141 (b) 1728 (c) 2081
  18. 18.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  19. 19.Which of these is a perfect cube? (a) 381 (b) 343 (c) 369
  20. 20.What is 20³? =
  21. 21.What is ∛4096? =
  22. 22.What is ∛9261? =
  23. 23.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  24. 24.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  25. 25.Which of these is a perfect cube? (a) 216 (b) 262 (c) 313
  26. 26.What is 3³? =
  27. 27.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  28. 28.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  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 125 cubic cm. How long is each edge (in cm)?
  31. 31.What is ∛8? =
  32. 32.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  33. 33.Which of these is a perfect cube? (a) 1000 (b) 1124 (c) 1076
  34. 34.Which of these is a perfect cube? (a) 2786 (b) 2837 (c) 2744
  35. 35.Which of these is a perfect cube? (a) 31 (b) 35 (c) 27
  36. 36.Which of these is a perfect cube? (a) 163 (b) 125 (c) 194
  37. 37.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  38. 38.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  39. 39.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  40. 40.What is 15³? =

Answer key

  1. 216
  2. 2744
  3. 512
  4. 17
  5. 216
  6. 3
  7. 3
  8. 64
  9. 20
  10. 11
  11. 19
  12. 10
  13. 6
  14. 8
  15. 49
  16. 64
  17. 1728
  18. 9
  19. 343
  20. 8000
  21. 16
  22. 21
  23. 27
  24. 4
  25. 216
  26. 27
  27. 5
  28. 5
  29. 13
  30. 5
  31. 2
  32. 19
  33. 1000
  34. 2744
  35. 27
  36. 125
  37. 5
  38. 16
  39. 3
  40. 3375

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