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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 889 · 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.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  3. 3.What is ∛15625? =
  4. 4.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  5. 5.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  6. 6.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  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.Which of these is a perfect cube? (a) 3681 (b) 3835 (c) 3375
  9. 9.What is 9³? =
  10. 10.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  11. 11.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  12. 12.Which of these is a perfect cube? (a) 285 (b) 216 (c) 261
  13. 13.What is 19³? =
  14. 14.What is 4³? =
  15. 15.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  16. 16.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  17. 17.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  18. 18.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  19. 19.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  20. 20.What is ∛3375? =
  21. 21.What is ∛125? =
  22. 22.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  23. 23.What is 8³? =
  24. 24.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  25. 25.What is 7³? =
  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 875 must be divided to get a perfect cube?
  28. 28.Which of these is a perfect cube? (a) 891 (b) 729 (c) 876
  29. 29.Which of these is a perfect cube? (a) 1331 (b) 1467 (c) 1553
  30. 30.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  31. 31.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  32. 32.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  33. 33.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  34. 34.What is 3³? =
  35. 35.What is ∛9261? =
  36. 36.What is the smallest whole number by which 256 must be divided to get a perfect cube?
  37. 37.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  38. 38.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  39. 39.What is ∛5832? =
  40. 40.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?

Answer key

  1. 216
  2. 8
  3. 25
  4. 27
  5. 7
  6. 10
  7. 64
  8. 3375
  9. 729
  10. 125
  11. 3
  12. 216
  13. 6859
  14. 64
  15. 9
  16. 27
  17. 4
  18. 25
  19. 7
  20. 15
  21. 5
  22. 14
  23. 512
  24. 2
  25. 343
  26. 6
  27. 7
  28. 729
  29. 1331
  30. 216
  31. 8
  32. 15
  33. 5
  34. 27
  35. 21
  36. 4
  37. 9
  38. 216
  39. 18
  40. 20

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