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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 535 · 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 ∛9261? =
  2. 2.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  3. 3.What is 8³? =
  4. 4.What is ∛64? =
  5. 5.What is ∛729? =
  6. 6.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  7. 7.What is ∛1331? =
  8. 8.Which of these is a perfect cube? (a) 1728 (b) 1957 (c) 2010
  9. 9.Which of these is a perfect cube? (a) 920 (b) 729 (c) 865
  10. 10.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  11. 11.What is ∛12167? =
  12. 12.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  13. 13.What is 6³? =
  14. 14.What is 4³? =
  15. 15.What is 10³? =
  16. 16.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  17. 17.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  18. 18.What is ∛343? =
  19. 19.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  20. 20.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  21. 21.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  22. 22.What is ∛6859? =
  23. 23.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  24. 24.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  25. 25.What is ∛512? =
  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 200 must be divided to get a perfect cube?
  28. 28.Which of these is a perfect cube? (a) 67 (b) 64 (c) 99
  29. 29.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  30. 30.What is ∛1728? =
  31. 31.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  32. 32.What is 7³? =
  33. 33.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  34. 34.Which of these is a perfect cube? (a) 2447 (b) 2197 (c) 2329
  35. 35.What is 15³? =
  36. 36.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  37. 37.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  38. 38.What is 5³? =
  39. 39.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  40. 40.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?

Answer key

  1. 21
  2. 27
  3. 512
  4. 4
  5. 9
  6. 216
  7. 11
  8. 1728
  9. 729
  10. 216
  11. 23
  12. 125
  13. 216
  14. 64
  15. 1000
  16. 9
  17. 4
  18. 7
  19. 49
  20. 20
  21. 5
  22. 19
  23. 19
  24. 13
  25. 8
  26. 6
  27. 25
  28. 64
  29. 12
  30. 12
  31. 17
  32. 343
  33. 49
  34. 2197
  35. 3375
  36. 64
  37. 27
  38. 125
  39. 49
  40. 7

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