← Cubes and cube roots lesson New set →

Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 687 · 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 cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  2. 2.What is 17³? =
  3. 3.What is ∛6859? =
  4. 4.Which of these is a perfect cube? (a) 53 (b) 27 (c) 42
  5. 5.What is 20³? =
  6. 6.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  7. 7.Which of these is a perfect cube? (a) 778 (b) 899 (c) 729
  8. 8.What is 4³? =
  9. 9.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  11. 11.What is 2³? =
  12. 12.What is 8³? =
  13. 13.What is 9³? =
  14. 14.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  15. 15.Which of these is a perfect cube? (a) 126 (b) 156 (c) 125
  16. 16.What is ∛13824? =
  17. 17.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  18. 18.Which of these is a perfect cube? (a) 1545 (b) 1667 (c) 1331
  19. 19.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  20. 20.What is 5³? =
  21. 21.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  22. 22.Which of these is a perfect cube? (a) 66 (b) 71 (c) 64
  23. 23.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  24. 24.Which of these is a perfect cube? (a) 1135 (b) 1299 (c) 1000
  25. 25.What is the smallest whole number by which 5400 must be divided to get a perfect cube?
  26. 26.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  27. 27.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  28. 28.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  29. 29.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  30. 30.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  31. 31.Which of these is a perfect cube? (a) 2304 (b) 2199 (c) 2197
  32. 32.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  33. 33.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  34. 34.What is ∛3375? =
  35. 35.What is 18³? =
  36. 36.What is 12³? =
  37. 37.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  38. 38.What is 7³? =
  39. 39.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
  40. 40.Which of these is a perfect cube? (a) 3120 (b) 2744 (c) 3241

Answer key

  1. 3
  2. 4913
  3. 19
  4. 27
  5. 8000
  6. 8
  7. 729
  8. 64
  9. 216
  10. 64
  11. 8
  12. 512
  13. 729
  14. 4
  15. 125
  16. 24
  17. 9
  18. 1331
  19. 4
  20. 125
  21. 8
  22. 64
  23. 64
  24. 1000
  25. 25
  26. 125
  27. 9
  28. 27
  29. 2
  30. 8
  31. 2197
  32. 2
  33. 49
  34. 15
  35. 5832
  36. 1728
  37. 125
  38. 343
  39. 9
  40. 2744

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