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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 880 · 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 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  2. 2.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  3. 3.Which of these is a perfect cube? (a) 2095 (b) 1728 (c) 1867
  4. 4.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  5. 5.What is ∛64? =
  6. 6.Which of these is a perfect cube? (a) 229 (b) 248 (c) 216
  7. 7.What is 15³? =
  8. 8.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  9. 9.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  10. 10.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  11. 11.Which of these is a perfect cube? (a) 127 (b) 125 (c) 185
  12. 12.What is ∛125? =
  13. 13.What is the smallest whole number by which 675 must be divided to get a perfect cube?
  14. 14.What is ∛4096? =
  15. 15.Which of these is a perfect cube? (a) 798 (b) 739 (c) 729
  16. 16.What is 11³? =
  17. 17.What is 6³? =
  18. 18.What is 18³? =
  19. 19.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  20. 20.What is 2³? =
  21. 21.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  22. 22.What is 9³? =
  23. 23.Which of these is a perfect cube? (a) 1288 (b) 1109 (c) 1000
  24. 24.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  25. 25.What is ∛343? =
  26. 26.What is ∛1000? =
  27. 27.What is ∛8? =
  28. 28.Which of these is a perfect cube? (a) 2489 (b) 2197 (c) 2642
  29. 29.What is 4³? =
  30. 30.Which of these is a perfect cube? (a) 343 (b) 404 (c) 463
  31. 31.What is the smallest whole number by which 500 must be multiplied to get a perfect cube?
  32. 32.Which of these is a perfect cube? (a) 27 (b) 35 (c) 31
  33. 33.What is the smallest whole number by which 1512 must be divided to get a perfect cube?
  34. 34.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  35. 35.Which of these is a perfect cube? (a) 512 (b) 704 (c) 546
  36. 36.What is ∛729? =
  37. 37.What is 19³? =
  38. 38.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  39. 39.What is ∛13824? =
  40. 40.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?

Answer key

  1. 125
  2. 4
  3. 1728
  4. 2
  5. 4
  6. 216
  7. 3375
  8. 2
  9. 3
  10. 6
  11. 125
  12. 5
  13. 25
  14. 16
  15. 729
  16. 1331
  17. 216
  18. 5832
  19. 8
  20. 8
  21. 9
  22. 729
  23. 1000
  24. 27
  25. 7
  26. 10
  27. 2
  28. 2197
  29. 64
  30. 343
  31. 2
  32. 27
  33. 7
  34. 125
  35. 512
  36. 9
  37. 6859
  38. 216
  39. 24
  40. 25

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