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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 623 · 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 10584 must be divided to get a perfect cube?
  2. 2.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  3. 3.What is ∛4096? =
  4. 4.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  5. 5.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  6. 6.What is the smallest whole number by which 5 must be divided to get a perfect cube?
  7. 7.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  8. 8.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  9. 9.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  10. 10.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  11. 11.What is 16³? =
  12. 12.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  13. 13.Which of these is a perfect cube? (a) 125 (b) 183 (c) 172
  14. 14.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  15. 15.What is ∛3375? =
  16. 16.What is 14³? =
  17. 17.Which of these is a perfect cube? (a) 3145 (b) 2828 (c) 2744
  18. 18.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  19. 19.Which of these is a perfect cube? (a) 3593 (b) 3661 (c) 3375
  20. 20.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  21. 21.What is ∛6859? =
  22. 22.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  23. 23.What is ∛8? =
  24. 24.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  25. 25.What is 2³? =
  26. 26.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  27. 27.What is the smallest whole number by which 648 must be multiplied to get a perfect cube?
  28. 28.What is ∛10648? =
  29. 29.What is 18³? =
  30. 30.What is 3³? =
  31. 31.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 216 (b) 266 (c) 296
  33. 33.Which of these is a perfect cube? (a) 2295 (b) 2485 (c) 2197
  34. 34.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  35. 35.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  36. 36.Which of these is a perfect cube? (a) 393 (b) 366 (c) 343
  37. 37.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  38. 38.What is ∛729? =
  39. 39.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  40. 40.Which of these is a perfect cube? (a) 1171 (b) 1087 (c) 1000

Answer key

  1. 49
  2. 125
  3. 16
  4. 19
  5. 7
  6. 5
  7. 14
  8. 8
  9. 49
  10. 13
  11. 4096
  12. 216
  13. 125
  14. 3
  15. 15
  16. 2744
  17. 2744
  18. 11
  19. 3375
  20. 3
  21. 19
  22. 125
  23. 2
  24. 9
  25. 8
  26. 64
  27. 9
  28. 22
  29. 5832
  30. 27
  31. 64
  32. 216
  33. 2197
  34. 216
  35. 2
  36. 343
  37. 5
  38. 9
  39. 2
  40. 1000

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