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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 517 · 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 2³? =
  2. 2.What is ∛343? =
  3. 3.What is the smallest whole number by which 500 must be divided to get a perfect cube?
  4. 4.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  5. 5.What is 7³? =
  6. 6.What is 4³? =
  7. 7.What is ∛4913? =
  8. 8.Which of these is a perfect cube? (a) 2197 (b) 2644 (c) 2243
  9. 9.What is ∛216? =
  10. 10.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  11. 11.What is ∛1000? =
  12. 12.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  13. 13.What is ∛1728? =
  14. 14.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  15. 15.What is 19³? =
  16. 16.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  17. 17.What is 18³? =
  18. 18.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  19. 19.Which of these is a perfect cube? (a) 216 (b) 287 (c) 281
  20. 20.What is 12³? =
  21. 21.What is 5³? =
  22. 22.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  23. 23.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  24. 24.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  25. 25.Which of these is a perfect cube? (a) 1971 (b) 2021 (c) 1728
  26. 26.Which of these is a perfect cube? (a) 512 (b) 645 (c) 620
  27. 27.What is 17³? =
  28. 28.Which of these is a perfect cube? (a) 27 (b) 31 (c) 53
  29. 29.What is ∛125? =
  30. 30.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  31. 31.Which of these is a perfect cube? (a) 1292 (b) 1266 (c) 1000
  32. 32.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  33. 33.What is ∛10648? =
  34. 34.What is 11³? =
  35. 35.What is ∛1331? =
  36. 36.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  37. 37.What is 15³? =
  38. 38.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  39. 39.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  40. 40.What is ∛3375? =

Answer key

  1. 8
  2. 7
  3. 4
  4. 3
  5. 343
  6. 64
  7. 17
  8. 2197
  9. 6
  10. 25
  11. 10
  12. 4
  13. 12
  14. 18
  15. 6859
  16. 4
  17. 5832
  18. 4
  19. 216
  20. 1728
  21. 125
  22. 8
  23. 8
  24. 125
  25. 1728
  26. 512
  27. 4913
  28. 27
  29. 5
  30. 25
  31. 1000
  32. 5
  33. 22
  34. 1331
  35. 11
  36. 3
  37. 3375
  38. 8
  39. 216
  40. 15

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