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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 898 · 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 4³? =
  2. 2.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  3. 3.What is ∛216? =
  4. 4.Which of these is a perfect cube? (a) 512 (b) 655 (c) 584
  5. 5.What is ∛64? =
  6. 6.Which of these is a perfect cube? (a) 1728 (b) 1838 (c) 1920
  7. 7.What is the smallest whole number by which 72 must be multiplied to get a perfect cube?
  8. 8.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛27? =
  10. 10.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  11. 11.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  12. 12.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  13. 13.What is 15³? =
  14. 14.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  15. 15.What is ∛8000? =
  16. 16.Which of these is a perfect cube? (a) 75 (b) 76 (c) 64
  17. 17.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  18. 18.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
  19. 19.What is ∛10648? =
  20. 20.Which of these is a perfect cube? (a) 1692 (b) 1331 (c) 1356
  21. 21.What is 2³? =
  22. 22.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
  23. 23.What is ∛6859? =
  24. 24.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  25. 25.What is ∛125? =
  26. 26.What is 17³? =
  27. 27.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  28. 28.Which of these is a perfect cube? (a) 125 (b) 184 (c) 133
  29. 29.What is 16³? =
  30. 30.What is ∛2197? =
  31. 31.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  32. 32.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  33. 33.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  34. 34.Which of these is a perfect cube? (a) 35 (b) 54 (c) 27
  35. 35.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  36. 36.What is 20³? =
  37. 37.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  38. 38.Which of these is a perfect cube? (a) 377 (b) 426 (c) 343
  39. 39.What is 7³? =
  40. 40.Which of these is a perfect cube? (a) 861 (b) 797 (c) 729

Answer key

  1. 64
  2. 3
  3. 6
  4. 512
  5. 4
  6. 1728
  7. 3
  8. 7
  9. 3
  10. 19
  11. 5
  12. 2
  13. 3375
  14. 7
  15. 20
  16. 64
  17. 8
  18. 49
  19. 22
  20. 1331
  21. 8
  22. 49
  23. 19
  24. 15
  25. 5
  26. 4913
  27. 125
  28. 125
  29. 4096
  30. 13
  31. 27
  32. 4
  33. 9
  34. 27
  35. 6
  36. 8000
  37. 16
  38. 343
  39. 343
  40. 729

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