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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 108 · 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 9³? =
  2. 2.What is ∛4096? =
  3. 3.What is 6³? =
  4. 4.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  5. 5.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  6. 6.What is 17³? =
  7. 7.Which of these is a perfect cube? (a) 82 (b) 79 (c) 64
  8. 8.Which of these is a perfect cube? (a) 343 (b) 348 (c) 405
  9. 9.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  10. 10.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  11. 11.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  12. 12.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  13. 13.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
  14. 14.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  15. 15.What is ∛4913? =
  16. 16.What is 2³? =
  17. 17.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  18. 18.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  19. 19.What is 15³? =
  20. 20.What is 20³? =
  21. 21.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  22. 22.What is ∛1000? =
  23. 23.What is 16³? =
  24. 24.Which of these is a perfect cube? (a) 2377 (b) 2445 (c) 2197
  25. 25.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  26. 26.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  27. 27.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  28. 28.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  29. 29.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  30. 30.Which of these is a perfect cube? (a) 729 (b) 927 (c) 808
  31. 31.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  32. 32.What is ∛729? =
  33. 33.Which of these is a perfect cube? (a) 1984 (b) 1983 (c) 1728
  34. 34.Which of these is a perfect cube? (a) 27 (b) 46 (c) 35
  35. 35.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  36. 36.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  37. 37.What is ∛216? =
  38. 38.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  39. 39.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  40. 40.What is ∛125? =

Answer key

  1. 729
  2. 16
  3. 216
  4. 19
  5. 64
  6. 4913
  7. 64
  8. 343
  9. 9
  10. 64
  11. 18
  12. 8
  13. 7
  14. 2
  15. 17
  16. 8
  17. 11
  18. 5
  19. 3375
  20. 8000
  21. 2
  22. 10
  23. 4096
  24. 2197
  25. 20
  26. 9
  27. 17
  28. 5
  29. 49
  30. 729
  31. 27
  32. 9
  33. 1728
  34. 27
  35. 2
  36. 8
  37. 6
  38. 216
  39. 6
  40. 5

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