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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 961 · 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 ∛4913? =
  2. 2.Which of these is a perfect cube? (a) 81 (b) 73 (c) 64
  3. 3.What is ∛2197? =
  4. 4.What is ∛729? =
  5. 5.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  6. 6.What is 4³? =
  7. 7.What is ∛8? =
  8. 8.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛13824? =
  10. 10.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
  11. 11.Which of these is a perfect cube? (a) 53 (b) 45 (c) 27
  12. 12.Which of these is a perfect cube? (a) 2575 (b) 2197 (c) 2256
  13. 13.What is ∛6859? =
  14. 14.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  15. 15.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  16. 16.Which of these is a perfect cube? (a) 234 (b) 216 (c) 280
  17. 17.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  18. 18.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  19. 19.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  20. 20.What is 18³? =
  21. 21.What is 12³? =
  22. 22.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  23. 23.What is ∛27? =
  24. 24.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  25. 25.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  26. 26.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  27. 27.What is 9³? =
  28. 28.What is ∛9261? =
  29. 29.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  30. 30.What is ∛2744? =
  31. 31.What is 5³? =
  32. 32.What is 3³? =
  33. 33.Which of these is a perfect cube? (a) 1728 (b) 2057 (c) 1818
  34. 34.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  35. 35.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  36. 36.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  37. 37.Which of these is a perfect cube? (a) 966 (b) 729 (c) 949
  38. 38.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  39. 39.What is 7³? =
  40. 40.What is the smallest whole number by which 648 must be multiplied to get a perfect cube?

Answer key

  1. 17
  2. 64
  3. 13
  4. 9
  5. 27
  6. 64
  7. 2
  8. 20
  9. 24
  10. 49
  11. 27
  12. 2197
  13. 19
  14. 2
  15. 27
  16. 216
  17. 4
  18. 8
  19. 9
  20. 5832
  21. 1728
  22. 18
  23. 3
  24. 125
  25. 25
  26. 49
  27. 729
  28. 21
  29. 12
  30. 14
  31. 125
  32. 27
  33. 1728
  34. 13
  35. 3
  36. 2
  37. 729
  38. 5
  39. 343
  40. 9

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