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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 470 · 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.Which of these is a perfect cube? (a) 2197 (b) 2601 (c) 2504
  2. 2.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  3. 3.Which of these is a perfect cube? (a) 343 (b) 406 (c) 473
  4. 4.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  5. 5.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  6. 6.What is 8³? =
  7. 7.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  8. 8.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  9. 9.What is the smallest whole number by which 3136 must be divided to get a perfect cube?
  10. 10.What is 20³? =
  11. 11.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  12. 12.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  13. 13.What is 2³? =
  14. 14.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  15. 15.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  16. 16.Which of these is a perfect cube? (a) 1262 (b) 1097 (c) 1000
  17. 17.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  18. 18.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  19. 19.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  20. 20.What is 12³? =
  21. 21.What is 13³? =
  22. 22.Which of these is a perfect cube? (a) 703 (b) 628 (c) 512
  23. 23.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  24. 24.What is ∛8000? =
  25. 25.What is ∛4913? =
  26. 26.What is ∛15625? =
  27. 27.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  28. 28.What is ∛10648? =
  29. 29.What is 15³? =
  30. 30.What is 19³? =
  31. 31.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  32. 32.Which of these is a perfect cube? (a) 306 (b) 269 (c) 216
  33. 33.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  34. 34.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  35. 35.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  36. 36.What is ∛343? =
  37. 37.What is 10³? =
  38. 38.What is the smallest whole number by which 56 must be divided to get a perfect cube?
  39. 39.What is ∛13824? =
  40. 40.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?

Answer key

  1. 2197
  2. 5
  3. 343
  4. 19
  5. 5
  6. 512
  7. 25
  8. 7
  9. 49
  10. 8000
  11. 125
  12. 14
  13. 8
  14. 7
  15. 27
  16. 1000
  17. 125
  18. 49
  19. 9
  20. 1728
  21. 2197
  22. 512
  23. 216
  24. 20
  25. 17
  26. 25
  27. 125
  28. 22
  29. 3375
  30. 6859
  31. 16
  32. 216
  33. 3
  34. 6
  35. 7
  36. 7
  37. 1000
  38. 7
  39. 24
  40. 49

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