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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 499 · 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.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  3. 3.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  4. 4.What is 6³? =
  5. 5.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
  6. 6.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  7. 7.What is 20³? =
  8. 8.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  9. 9.What is 2³? =
  10. 10.What is ∛3375? =
  11. 11.Which of these is a perfect cube? (a) 2744 (b) 3305 (c) 3255
  12. 12.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  13. 13.What is 13³? =
  14. 14.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  15. 15.What is ∛27? =
  16. 16.What is ∛64? =
  17. 17.What is ∛1000? =
  18. 18.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  19. 19.What is ∛8? =
  20. 20.What is the smallest whole number by which 250 must be divided to get a perfect cube?
  21. 21.Which of these is a perfect cube? (a) 240 (b) 228 (c) 216
  22. 22.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  23. 23.Which of these is a perfect cube? (a) 27 (b) 50 (c) 54
  24. 24.Which of these is a perfect cube? (a) 143 (b) 127 (c) 125
  25. 25.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  26. 26.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  27. 27.Which of these is a perfect cube? (a) 1753 (b) 1853 (c) 1728
  28. 28.Which of these is a perfect cube? (a) 512 (b) 652 (c) 580
  29. 29.What is ∛2197? =
  30. 30.What is ∛343? =
  31. 31.What is ∛512? =
  32. 32.Which of these is a perfect cube? (a) 2267 (b) 2197 (c) 2437
  33. 33.Which of these is a perfect cube? (a) 3375 (b) 3524 (c) 3882
  34. 34.What is 4³? =
  35. 35.What is 17³? =
  36. 36.What is ∛4913? =
  37. 37.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  38. 38.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  39. 39.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  40. 40.Which of these is a perfect cube? (a) 742 (b) 729 (c) 964

Answer key

  1. 3
  2. 5
  3. 6
  4. 216
  5. 9
  6. 64
  7. 8000
  8. 8
  9. 8
  10. 15
  11. 2744
  12. 125
  13. 2197
  14. 3
  15. 3
  16. 4
  17. 10
  18. 8
  19. 2
  20. 2
  21. 216
  22. 9
  23. 27
  24. 125
  25. 49
  26. 2
  27. 1728
  28. 512
  29. 13
  30. 7
  31. 8
  32. 2197
  33. 3375
  34. 64
  35. 4913
  36. 17
  37. 7
  38. 2
  39. 17
  40. 729

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