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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 296 · 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.Which of these is a perfect cube? (a) 190 (b) 125 (c) 163
  2. 2.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  3. 3.Which of these is a perfect cube? (a) 1102 (b) 1000 (c) 1212
  4. 4.Which of these is a perfect cube? (a) 254 (b) 297 (c) 216
  5. 5.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  6. 6.What is ∛10648? =
  7. 7.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  8. 8.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  9. 9.What is 3³? =
  10. 10.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  11. 11.What is 16³? =
  12. 12.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  13. 13.What is ∛4913? =
  14. 14.What is 2³? =
  15. 15.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  16. 16.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  17. 17.What is 19³? =
  18. 18.What is 11³? =
  19. 19.What is the smallest whole number by which 24 must be divided to get a perfect cube?
  20. 20.What is 20³? =
  21. 21.Which of these is a perfect cube? (a) 1635 (b) 1331 (c) 1435
  22. 22.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  23. 23.What is 10³? =
  24. 24.Which of these is a perfect cube? (a) 343 (b) 475 (c) 344
  25. 25.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  26. 26.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  27. 27.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  28. 28.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  29. 29.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  30. 30.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  31. 31.What is 14³? =
  32. 32.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  33. 33.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  34. 34.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  35. 35.What is 17³? =
  36. 36.What is 18³? =
  37. 37.What is ∛3375? =
  38. 38.Which of these is a perfect cube? (a) 2197 (b) 2539 (c) 2330
  39. 39.What is ∛4096? =
  40. 40.Which of these is a perfect cube? (a) 743 (b) 837 (c) 729

Answer key

  1. 125
  2. 216
  3. 1000
  4. 216
  5. 5
  6. 22
  7. 8
  8. 25
  9. 27
  10. 14
  11. 4096
  12. 12
  13. 17
  14. 8
  15. 2
  16. 64
  17. 6859
  18. 1331
  19. 3
  20. 8000
  21. 1331
  22. 125
  23. 1000
  24. 343
  25. 4
  26. 6
  27. 4
  28. 3
  29. 49
  30. 8
  31. 2744
  32. 7
  33. 8
  34. 27
  35. 4913
  36. 5832
  37. 15
  38. 2197
  39. 16
  40. 729

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