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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 502 · 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 ∛6859? =
  2. 2.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  3. 3.Which of these is a perfect cube? (a) 1073 (b) 1040 (c) 1000
  4. 4.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  5. 5.What is ∛5832? =
  6. 6.What is 2³? =
  7. 7.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  8. 8.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛3375? =
  10. 10.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  11. 11.What is ∛8? =
  12. 12.What is ∛125? =
  13. 13.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  14. 14.What is ∛1728? =
  15. 15.What is ∛2197? =
  16. 16.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  17. 17.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  18. 18.What is the smallest whole number by which 1080 must be divided to get a perfect cube?
  19. 19.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
  20. 20.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  21. 21.What is 5³? =
  22. 22.Which of these is a perfect cube? (a) 95 (b) 64 (c) 96
  23. 23.What is 14³? =
  24. 24.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  25. 25.What is 11³? =
  26. 26.What is ∛15625? =
  27. 27.Which of these is a perfect cube? (a) 27 (b) 34 (c) 32
  28. 28.What is ∛8000? =
  29. 29.What is 7³? =
  30. 30.What is 19³? =
  31. 31.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  32. 32.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
  33. 33.Which of these is a perfect cube? (a) 1431 (b) 1633 (c) 1331
  34. 34.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  35. 35.What is 6³? =
  36. 36.What is ∛729? =
  37. 37.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  38. 38.What is ∛27? =
  39. 39.Which of these is a perfect cube? (a) 2245 (b) 2297 (c) 2197
  40. 40.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?

Answer key

  1. 19
  2. 2
  3. 1000
  4. 14
  5. 18
  6. 8
  7. 64
  8. 6
  9. 15
  10. 8
  11. 2
  12. 5
  13. 216
  14. 12
  15. 13
  16. 5
  17. 13
  18. 5
  19. 3
  20. 27
  21. 125
  22. 64
  23. 2744
  24. 15
  25. 1331
  26. 25
  27. 27
  28. 20
  29. 343
  30. 6859
  31. 20
  32. 49
  33. 1331
  34. 125
  35. 216
  36. 9
  37. 7
  38. 3
  39. 2197
  40. 3

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