← Cubes and cube roots lesson New set →

Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 796 · 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 divided to get a perfect cube?
  2. 2.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  3. 3.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  4. 4.What is 18³? =
  5. 5.What is 13³? =
  6. 6.Which of these is a perfect cube? (a) 439 (b) 364 (c) 343
  7. 7.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  8. 8.What is ∛3375? =
  9. 9.What is 19³? =
  10. 10.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  11. 11.What is 6³? =
  12. 12.Which of these is a perfect cube? (a) 838 (b) 775 (c) 729
  13. 13.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  14. 14.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  15. 15.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  16. 16.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  17. 17.What is 8³? =
  18. 18.What is the smallest whole number by which 72 must be divided to get a perfect cube?
  19. 19.What is the smallest whole number by which 189 must be divided to get a perfect cube?
  20. 20.Which of these is a perfect cube? (a) 1728 (b) 1781 (c) 1998
  21. 21.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  22. 22.What is 3³? =
  23. 23.What is ∛8? =
  24. 24.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  25. 25.Which of these is a perfect cube? (a) 27 (b) 39 (c) 50
  26. 26.What is ∛8000? =
  27. 27.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  28. 28.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  29. 29.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  30. 30.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  31. 31.What is ∛1331? =
  32. 32.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  33. 33.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  34. 34.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
  35. 35.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  36. 36.What is 12³? =
  37. 37.What is 20³? =
  38. 38.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  39. 39.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  40. 40.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?

Answer key

  1. 3
  2. 27
  3. 125
  4. 5832
  5. 2197
  6. 343
  7. 2
  8. 15
  9. 6859
  10. 8
  11. 216
  12. 729
  13. 4
  14. 27
  15. 4
  16. 3
  17. 512
  18. 9
  19. 7
  20. 1728
  21. 2
  22. 27
  23. 2
  24. 7
  25. 27
  26. 20
  27. 13
  28. 8
  29. 25
  30. 7
  31. 11
  32. 20
  33. 49
  34. 2
  35. 3
  36. 1728
  37. 8000
  38. 125
  39. 64
  40. 8

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