← Cubes and cube roots lesson New set →

Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 878 · 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.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  2. 2.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  3. 3.What is 19³? =
  4. 4.What is 5³? =
  5. 5.What is 14³? =
  6. 6.What is ∛729? =
  7. 7.What is ∛3375? =
  8. 8.What is the smallest whole number by which 25 must be divided to get a perfect cube?
  9. 9.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  10. 10.What is the smallest whole number by which 135 must be multiplied to get a perfect cube?
  11. 11.What is ∛6859? =
  12. 12.What is ∛8000? =
  13. 13.What is 10³? =
  14. 14.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  15. 15.Which of these is a perfect cube? (a) 64 (b) 69 (c) 107
  16. 16.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  17. 17.What is ∛343? =
  18. 18.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  19. 19.What is 6³? =
  20. 20.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  21. 21.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  22. 22.What is 9³? =
  23. 23.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  24. 24.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  25. 25.What is 8³? =
  26. 26.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  27. 27.Which of these is a perfect cube? (a) 541 (b) 691 (c) 512
  28. 28.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  29. 29.Which of these is a perfect cube? (a) 47 (b) 27 (c) 46
  30. 30.Which of these is a perfect cube? (a) 1258 (b) 1000 (c) 1218
  31. 31.Which of these is a perfect cube? (a) 298 (b) 236 (c) 216
  32. 32.What is 18³? =
  33. 33.What is 13³? =
  34. 34.What is ∛125? =
  35. 35.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  36. 36.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  37. 37.What is ∛1000? =
  38. 38.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  39. 39.What is 20³? =
  40. 40.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?

Answer key

  1. 216
  2. 3
  3. 6859
  4. 125
  5. 2744
  6. 9
  7. 15
  8. 25
  9. 19
  10. 25
  11. 19
  12. 20
  13. 1000
  14. 16
  15. 64
  16. 2
  17. 7
  18. 49
  19. 216
  20. 4
  21. 15
  22. 729
  23. 2
  24. 27
  25. 512
  26. 13
  27. 512
  28. 125
  29. 27
  30. 1000
  31. 216
  32. 5832
  33. 2197
  34. 5
  35. 7
  36. 64
  37. 10
  38. 8
  39. 8000
  40. 7

Free maths worksheets lessons, practice and worksheets at talentjr.in/maths-worksheets