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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 54 · 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 ∛343? =
  2. 2.Which of these is a perfect cube? (a) 2666 (b) 2568 (c) 2197
  3. 3.What is the smallest whole number by which 5 must be divided to get a perfect cube?
  4. 4.What is 16³? =
  5. 5.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  6. 6.What is 20³? =
  7. 7.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  8. 8.What is ∛1331? =
  9. 9.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  10. 10.What is 13³? =
  11. 11.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  12. 12.Which of these is a perfect cube? (a) 3375 (b) 3545 (c) 3382
  13. 13.What is 19³? =
  14. 14.Which of these is a perfect cube? (a) 1152 (b) 1128 (c) 1000
  15. 15.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  16. 16.What is ∛12167? =
  17. 17.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
  18. 18.Which of these is a perfect cube? (a) 512 (b) 652 (c) 574
  19. 19.What is ∛4913? =
  20. 20.What is ∛2197? =
  21. 21.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  22. 22.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  23. 23.What is ∛13824? =
  24. 24.What is ∛64? =
  25. 25.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  26. 26.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  27. 27.Which of these is a perfect cube? (a) 83 (b) 69 (c) 64
  28. 28.What is the smallest whole number by which 3125 must be divided to get a perfect cube?
  29. 29.What is ∛1000? =
  30. 30.Which of these is a perfect cube? (a) 793 (b) 729 (c) 835
  31. 31.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  32. 32.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  33. 33.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  34. 34.What is 14³? =
  35. 35.What is 3³? =
  36. 36.What is 17³? =
  37. 37.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  38. 38.Which of these is a perfect cube? (a) 216 (b) 303 (c) 324
  39. 39.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  40. 40.What is ∛15625? =

Answer key

  1. 7
  2. 2197
  3. 5
  4. 4096
  5. 3
  6. 8000
  7. 216
  8. 11
  9. 25
  10. 2197
  11. 125
  12. 3375
  13. 6859
  14. 1000
  15. 8
  16. 23
  17. 49
  18. 512
  19. 17
  20. 13
  21. 6
  22. 64
  23. 24
  24. 4
  25. 27
  26. 13
  27. 64
  28. 25
  29. 10
  30. 729
  31. 216
  32. 25
  33. 5
  34. 2744
  35. 27
  36. 4913
  37. 64
  38. 216
  39. 8
  40. 25

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