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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 764 · 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 ∛4096? =
  2. 2.What is ∛1000? =
  3. 3.What is 3³? =
  4. 4.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  5. 5.What is 10³? =
  6. 6.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  7. 7.Which of these is a perfect cube? (a) 2781 (b) 3024 (c) 2744
  8. 8.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
  9. 9.What is ∛8? =
  10. 10.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  11. 11.Which of these is a perfect cube? (a) 52 (b) 27 (c) 46
  12. 12.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  13. 13.What is 13³? =
  14. 14.What is 7³? =
  15. 15.What is 18³? =
  16. 16.What is ∛13824? =
  17. 17.Which of these is a perfect cube? (a) 343 (b) 395 (c) 377
  18. 18.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  19. 19.What is ∛12167? =
  20. 20.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  21. 21.What is ∛27? =
  22. 22.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  23. 23.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  24. 24.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  25. 25.What is ∛4913? =
  26. 26.What is ∛1728? =
  27. 27.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  28. 28.What is the smallest whole number by which 675 must be multiplied to get a perfect cube?
  29. 29.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
  30. 30.What is the smallest whole number by which 243 must be multiplied to get a perfect cube?
  31. 31.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  32. 32.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  33. 33.What is ∛1331? =
  34. 34.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  35. 35.What is ∛512? =
  36. 36.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  37. 37.Which of these is a perfect cube? (a) 64 (b) 91 (c) 96
  38. 38.What is 17³? =
  39. 39.What is 12³? =
  40. 40.What is the smallest whole number by which 24 must be divided to get a perfect cube?

Answer key

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

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