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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 906 · 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 16³? =
  2. 2.Which of these is a perfect cube? (a) 803 (b) 729 (c) 771
  3. 3.What is ∛27? =
  4. 4.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  5. 5.Which of these is a perfect cube? (a) 147 (b) 131 (c) 125
  6. 6.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  7. 7.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  8. 8.Which of these is a perfect cube? (a) 3632 (b) 3613 (c) 3375
  9. 9.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  10. 10.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  11. 11.What is 20³? =
  12. 12.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  13. 13.What is ∛1728? =
  14. 14.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  15. 15.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  16. 16.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  17. 17.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  18. 18.What is the smallest whole number by which 7 must be divided to get a perfect cube?
  19. 19.What is ∛4096? =
  20. 20.What is 12³? =
  21. 21.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  22. 22.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  23. 23.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  24. 24.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  25. 25.What is ∛4913? =
  26. 26.Which of these is a perfect cube? (a) 216 (b) 316 (c) 290
  27. 27.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  28. 28.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  29. 29.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  30. 30.What is ∛9261? =
  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.What is ∛125? =
  33. 33.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  34. 34.What is ∛13824? =
  35. 35.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  36. 36.Which of these is a perfect cube? (a) 2976 (b) 2744 (c) 2965
  37. 37.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  38. 38.Which of these is a perfect cube? (a) 1593 (b) 1460 (c) 1331
  39. 39.What is ∛2744? =
  40. 40.What is 19³? =

Answer key

  1. 4096
  2. 729
  3. 3
  4. 18
  5. 125
  6. 2
  7. 3
  8. 3375
  9. 25
  10. 16
  11. 8000
  12. 2
  13. 12
  14. 8
  15. 5
  16. 4
  17. 216
  18. 7
  19. 16
  20. 1728
  21. 25
  22. 27
  23. 9
  24. 15
  25. 17
  26. 216
  27. 64
  28. 216
  29. 25
  30. 21
  31. 64
  32. 5
  33. 64
  34. 24
  35. 2
  36. 2744
  37. 7
  38. 1331
  39. 14
  40. 6859

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