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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 267 · 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 17³? =
  2. 2.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  3. 3.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  4. 4.What is ∛27? =
  5. 5.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  6. 6.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  7. 7.A big cube of edge 15 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) 198 (b) 188 (c) 125
  9. 9.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  10. 10.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  11. 11.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  12. 12.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  13. 13.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  14. 14.What is ∛343? =
  15. 15.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  16. 16.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  17. 17.What is ∛125? =
  18. 18.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  19. 19.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  20. 20.What is ∛2744? =
  21. 21.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  22. 22.What is 4³? =
  23. 23.Which of these is a perfect cube? (a) 549 (b) 512 (c) 580
  24. 24.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  25. 25.Which of these is a perfect cube? (a) 1818 (b) 2122 (c) 1728
  26. 26.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  27. 27.What is ∛64? =
  28. 28.What is ∛13824? =
  29. 29.What is 15³? =
  30. 30.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  31. 31.What is 13³? =
  32. 32.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  33. 33.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  34. 34.What is 5³? =
  35. 35.What is 9³? =
  36. 36.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  37. 37.What is the smallest whole number by which 1512 must be divided to get a perfect cube?
  38. 38.What is ∛4096? =
  39. 39.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  40. 40.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?

Answer key

  1. 4913
  2. 9
  3. 4
  4. 3
  5. 27
  6. 125
  7. 125
  8. 125
  9. 14
  10. 6
  11. 25
  12. 4
  13. 13
  14. 7
  15. 25
  16. 27
  17. 5
  18. 17
  19. 8
  20. 14
  21. 25
  22. 64
  23. 512
  24. 4
  25. 1728
  26. 27
  27. 4
  28. 24
  29. 3375
  30. 10
  31. 2197
  32. 9
  33. 216
  34. 125
  35. 729
  36. 16
  37. 7
  38. 16
  39. 19
  40. 27

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