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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 625 · 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 big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  2. 2.What is ∛6859? =
  3. 3.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  4. 4.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  5. 5.What is 5³? =
  6. 6.What is ∛729? =
  7. 7.What is 2³? =
  8. 8.What is 8³? =
  9. 9.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  10. 10.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  11. 11.A big cube of edge 3 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) 729 (b) 767 (c) 921
  13. 13.What is ∛4096? =
  14. 14.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  15. 15.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  16. 16.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  17. 17.What is ∛27? =
  18. 18.Which of these is a perfect cube? (a) 261 (b) 257 (c) 216
  19. 19.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  20. 20.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  21. 21.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  22. 22.What is 16³? =
  23. 23.What is 6³? =
  24. 24.Which of these is a perfect cube? (a) 2744 (b) 2758 (c) 3121
  25. 25.What is ∛125? =
  26. 26.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  27. 27.What is ∛2744? =
  28. 28.What is 9³? =
  29. 29.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  30. 30.What is ∛1331? =
  31. 31.What is 13³? =
  32. 32.What is 3³? =
  33. 33.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  34. 34.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
  35. 35.What is ∛12167? =
  36. 36.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  37. 37.What is the smallest whole number by which 72 must be divided to get a perfect cube?
  38. 38.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  39. 39.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
  40. 40.Which of these is a perfect cube? (a) 142 (b) 125 (c) 190

Answer key

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

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