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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 967 · 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.Which of these is a perfect cube? (a) 181 (b) 125 (c) 192
  2. 2.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  3. 3.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  4. 4.What is 15³? =
  5. 5.Which of these is a perfect cube? (a) 1494 (b) 1446 (c) 1331
  6. 6.Which of these is a perfect cube? (a) 42 (b) 39 (c) 27
  7. 7.What is 5³? =
  8. 8.What is 13³? =
  9. 9.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  10. 10.What is ∛343? =
  11. 11.What is ∛27? =
  12. 12.What is ∛9261? =
  13. 13.What is ∛125? =
  14. 14.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  15. 15.What is ∛1000? =
  16. 16.What is 12³? =
  17. 17.What is ∛8? =
  18. 18.Which of these is a perfect cube? (a) 382 (b) 343 (c) 380
  19. 19.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  20. 20.What is ∛4913? =
  21. 21.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  22. 22.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  23. 23.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  24. 24.What is 20³? =
  25. 25.What is 3³? =
  26. 26.What is ∛64? =
  27. 27.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  28. 28.What is ∛729? =
  29. 29.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  30. 30.Which of these is a perfect cube? (a) 2764 (b) 2744 (c) 3080
  31. 31.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  32. 32.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
  33. 33.What is 7³? =
  34. 34.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  35. 35.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  36. 36.Which of these is a perfect cube? (a) 2391 (b) 2197 (c) 2673
  37. 37.What is 18³? =
  38. 38.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  39. 39.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  40. 40.Which of these is a perfect cube? (a) 78 (b) 95 (c) 64

Answer key

  1. 125
  2. 9
  3. 27
  4. 3375
  5. 1331
  6. 27
  7. 125
  8. 2197
  9. 216
  10. 7
  11. 3
  12. 21
  13. 5
  14. 19
  15. 10
  16. 1728
  17. 2
  18. 343
  19. 16
  20. 17
  21. 10
  22. 12
  23. 27
  24. 8000
  25. 27
  26. 4
  27. 15
  28. 9
  29. 216
  30. 2744
  31. 8
  32. 49
  33. 343
  34. 5
  35. 13
  36. 2197
  37. 5832
  38. 25
  39. 9
  40. 64

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