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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 564 · 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 6³? =
  2. 2.Which of these is a perfect cube? (a) 601 (b) 512 (c) 592
  3. 3.What is the smallest whole number by which 7 must be divided to get a perfect cube?
  4. 4.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  5. 5.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
  6. 6.Which of these is a perfect cube? (a) 776 (b) 729 (c) 941
  7. 7.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  8. 8.What is 18³? =
  9. 9.What is ∛9261? =
  10. 10.What is 2³? =
  11. 11.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  12. 12.What is ∛1000? =
  13. 13.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  14. 14.What is 14³? =
  15. 15.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  16. 16.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  17. 17.What is 4³? =
  18. 18.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  19. 19.Which of these is a perfect cube? (a) 1872 (b) 1728 (c) 1830
  20. 20.Which of these is a perfect cube? (a) 1575 (b) 1331 (c) 1491
  21. 21.What is ∛64? =
  22. 22.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  23. 23.What is the smallest whole number by which 81 must be divided to get a perfect cube?
  24. 24.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  25. 25.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  26. 26.What is ∛27? =
  27. 27.Which of these is a perfect cube? (a) 235 (b) 268 (c) 216
  28. 28.What is ∛125? =
  29. 29.Which of these is a perfect cube? (a) 27 (b) 54 (c) 38
  30. 30.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  31. 31.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  32. 32.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  33. 33.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  34. 34.Which of these is a perfect cube? (a) 3886 (b) 3754 (c) 3375
  35. 35.Which of these is a perfect cube? (a) 64 (b) 102 (c) 70
  36. 36.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  37. 37.What is 7³? =
  38. 38.What is ∛343? =
  39. 39.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  40. 40.What is ∛1728? =

Answer key

  1. 216
  2. 512
  3. 7
  4. 18
  5. 3
  6. 729
  7. 4
  8. 5832
  9. 21
  10. 8
  11. 8
  12. 10
  13. 20
  14. 2744
  15. 2
  16. 4
  17. 64
  18. 8
  19. 1728
  20. 1331
  21. 4
  22. 216
  23. 3
  24. 3
  25. 27
  26. 3
  27. 216
  28. 5
  29. 27
  30. 125
  31. 9
  32. 7
  33. 8
  34. 3375
  35. 64
  36. 19
  37. 343
  38. 7
  39. 125
  40. 12

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