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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 11 · 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 the smallest whole number by which 108 must be divided to get a perfect cube?
  2. 2.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  3. 3.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  4. 4.What is the smallest whole number by which 3136 must be divided to get a perfect cube?
  5. 5.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  6. 6.What is ∛1000? =
  7. 7.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  8. 8.What is 10³? =
  9. 9.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  10. 10.What is ∛729? =
  11. 11.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  12. 12.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  13. 13.Which of these is a perfect cube? (a) 1790 (b) 1873 (c) 1728
  14. 14.What is the smallest whole number by which 5 must be divided to get a perfect cube?
  15. 15.What is 4³? =
  16. 16.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  17. 17.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  18. 18.What is 2³? =
  19. 19.Which of these is a perfect cube? (a) 765 (b) 729 (c) 795
  20. 20.What is the smallest whole number by which 81 must be divided to get a perfect cube?
  21. 21.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  22. 22.Which of these is a perfect cube? (a) 512 (b) 664 (c) 651
  23. 23.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  24. 24.What is 15³? =
  25. 25.What is 11³? =
  26. 26.What is 20³? =
  27. 27.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  28. 28.Which of these is a perfect cube? (a) 2589 (b) 2361 (c) 2197
  29. 29.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  30. 30.What is 13³? =
  31. 31.What is ∛343? =
  32. 32.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  33. 33.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  34. 34.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  35. 35.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  36. 36.What is 18³? =
  37. 37.What is 16³? =
  38. 38.Which of these is a perfect cube? (a) 1061 (b) 1000 (c) 1299
  39. 39.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  40. 40.What is 6³? =

Answer key

  1. 4
  2. 49
  3. 5
  4. 49
  5. 27
  6. 10
  7. 25
  8. 1000
  9. 49
  10. 9
  11. 216
  12. 11
  13. 1728
  14. 5
  15. 64
  16. 17
  17. 64
  18. 8
  19. 729
  20. 3
  21. 4
  22. 512
  23. 125
  24. 3375
  25. 1331
  26. 8000
  27. 4
  28. 2197
  29. 19
  30. 2197
  31. 7
  32. 216
  33. 12
  34. 49
  35. 6
  36. 5832
  37. 4096
  38. 1000
  39. 64
  40. 216

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