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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 216 · 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 cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  2. 2.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  3. 3.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  4. 4.Which of these is a perfect cube? (a) 559 (b) 512 (c) 520
  5. 5.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  6. 6.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  7. 7.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  8. 8.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
  9. 9.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  10. 10.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  11. 11.What is 18³? =
  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 4³? =
  14. 14.Which of these is a perfect cube? (a) 27 (b) 31 (c) 35
  15. 15.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  16. 16.What is 15³? =
  17. 17.What is ∛9261? =
  18. 18.Which of these is a perfect cube? (a) 3254 (b) 2744 (c) 3163
  19. 19.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  20. 20.What is ∛64? =
  21. 21.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  22. 22.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
  23. 23.What is ∛3375? =
  24. 24.What is 16³? =
  25. 25.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  26. 26.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  27. 27.What is 20³? =
  28. 28.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  29. 29.What is ∛8? =
  30. 30.Which of these is a perfect cube? (a) 378 (b) 343 (c) 449
  31. 31.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  32. 32.What is ∛2744? =
  33. 33.Which of these is a perfect cube? (a) 125 (b) 156 (c) 136
  34. 34.What is 9³? =
  35. 35.What is ∛1728? =
  36. 36.What is 14³? =
  37. 37.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  38. 38.What is the smallest whole number by which 189 must be divided to get a perfect cube?
  39. 39.Which of these is a perfect cube? (a) 1331 (b) 1355 (c) 1474
  40. 40.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?

Answer key

  1. 5
  2. 4
  3. 12
  4. 512
  5. 7
  6. 5
  7. 3
  8. 9
  9. 5
  10. 8
  11. 5832
  12. 8
  13. 64
  14. 27
  15. 8
  16. 3375
  17. 21
  18. 2744
  19. 125
  20. 4
  21. 216
  22. 49
  23. 15
  24. 4096
  25. 17
  26. 4
  27. 8000
  28. 13
  29. 2
  30. 343
  31. 216
  32. 14
  33. 125
  34. 729
  35. 12
  36. 2744
  37. 14
  38. 7
  39. 1331
  40. 49

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