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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 911 · 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 ∛4096? =
  2. 2.What is the smallest whole number by which 81 must be divided to get a perfect cube?
  3. 3.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  4. 4.Which of these is a perfect cube? (a) 64 (b) 87 (c) 79
  5. 5.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  6. 6.What is 6³? =
  7. 7.What is 16³? =
  8. 8.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  9. 9.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  11. 11.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  12. 12.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  13. 13.Which of these is a perfect cube? (a) 2197 (b) 2234 (c) 2684
  14. 14.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  15. 15.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
  16. 16.What is ∛1728? =
  17. 17.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  18. 18.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  19. 19.Which of these is a perfect cube? (a) 729 (b) 809 (c) 783
  20. 20.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
  21. 21.Which of these is a perfect cube? (a) 182 (b) 125 (c) 195
  22. 22.What is ∛343? =
  23. 23.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  24. 24.What is ∛5832? =
  25. 25.What is the smallest whole number by which 24 must be divided 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 14³? =
  28. 28.What is 2³? =
  29. 29.What is ∛13824? =
  30. 30.What is ∛12167? =
  31. 31.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  32. 32.What is ∛9261? =
  33. 33.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  34. 34.What is 13³? =
  35. 35.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  36. 36.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  37. 37.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
  38. 38.Which of these is a perfect cube? (a) 1345 (b) 1465 (c) 1331
  39. 39.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  40. 40.What is ∛4913? =

Answer key

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

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