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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 63 · 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 ∛15625? =
  2. 2.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  3. 3.What is ∛1000? =
  4. 4.Which of these is a perfect cube? (a) 1428 (b) 1331 (c) 1679
  5. 5.What is ∛9261? =
  6. 6.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  7. 7.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  8. 8.What is ∛5832? =
  9. 9.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  10. 10.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  11. 11.What is ∛1331? =
  12. 12.What is ∛4913? =
  13. 13.What is 14³? =
  14. 14.Which of these is a perfect cube? (a) 145 (b) 135 (c) 125
  15. 15.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  16. 16.Which of these is a perfect cube? (a) 65 (b) 104 (c) 64
  17. 17.Which of these is a perfect cube? (a) 374 (b) 455 (c) 343
  18. 18.What is ∛6859? =
  19. 19.Which of these is a perfect cube? (a) 216 (b) 310 (c) 253
  20. 20.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  21. 21.What is ∛10648? =
  22. 22.What is 13³? =
  23. 23.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  24. 24.Which of these is a perfect cube? (a) 1000 (b) 1205 (c) 1165
  25. 25.What is 6³? =
  26. 26.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  27. 27.What is 5³? =
  28. 28.What is ∛3375? =
  29. 29.What is the smallest whole number by which 5 must be divided to get a perfect cube?
  30. 30.What is 18³? =
  31. 31.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  32. 32.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  33. 33.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  34. 34.What is the smallest whole number by which 1512 must be divided to get a perfect cube?
  35. 35.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  36. 36.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  37. 37.What is ∛8000? =
  38. 38.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  39. 39.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  40. 40.What is 19³? =

Answer key

  1. 25
  2. 19
  3. 10
  4. 1331
  5. 21
  6. 7
  7. 27
  8. 18
  9. 64
  10. 125
  11. 11
  12. 17
  13. 2744
  14. 125
  15. 216
  16. 64
  17. 343
  18. 19
  19. 216
  20. 18
  21. 22
  22. 2197
  23. 12
  24. 1000
  25. 216
  26. 14
  27. 125
  28. 15
  29. 5
  30. 5832
  31. 3
  32. 6
  33. 17
  34. 7
  35. 7
  36. 125
  37. 20
  38. 8
  39. 9
  40. 6859

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