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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 208 · 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 the smallest whole number by which 81 must be multiplied to get a perfect cube?
  2. 2.What is 6³? =
  3. 3.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  4. 4.A big cube of edge 8 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 1944 must be multiplied to get a perfect cube?
  6. 6.What is ∛1000? =
  7. 7.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  8. 8.What is 10³? =
  9. 9.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  10. 10.What is ∛2744? =
  11. 11.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  12. 12.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  13. 13.What is ∛5832? =
  14. 14.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  15. 15.What is the smallest whole number by which 625 must be divided to get a perfect cube?
  16. 16.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  17. 17.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  18. 18.What is ∛729? =
  19. 19.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  20. 20.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  21. 21.What is 5³? =
  22. 22.Which of these is a perfect cube? (a) 397 (b) 343 (c) 456
  23. 23.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  24. 24.What is ∛27? =
  25. 25.What is ∛8000? =
  26. 26.Which of these is a perfect cube? (a) 199 (b) 142 (c) 125
  27. 27.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  28. 28.What is the smallest whole number by which 250 must be divided to get a perfect cube?
  29. 29.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  30. 30.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  31. 31.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  32. 32.What is 13³? =
  33. 33.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  34. 34.What is 11³? =
  35. 35.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  36. 36.What is 17³? =
  37. 37.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  38. 38.What is 14³? =
  39. 39.Which of these is a perfect cube? (a) 4004 (b) 3375 (c) 3860
  40. 40.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?

Answer key

  1. 9
  2. 216
  3. 216
  4. 8
  5. 3
  6. 10
  7. 5
  8. 1000
  9. 25
  10. 14
  11. 8
  12. 7
  13. 18
  14. 64
  15. 5
  16. 6
  17. 13
  18. 9
  19. 5
  20. 125
  21. 125
  22. 343
  23. 20
  24. 3
  25. 20
  26. 125
  27. 11
  28. 2
  29. 3
  30. 2
  31. 14
  32. 2197
  33. 4
  34. 1331
  35. 64
  36. 4913
  37. 8
  38. 2744
  39. 3375
  40. 2

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