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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 49 · 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 5832 cubic cm. How long is each edge (in cm)?
  2. 2.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  3. 3.What is the smallest whole number by which 500 must be multiplied to get a perfect cube?
  4. 4.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
  5. 5.What is ∛1728? =
  6. 6.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  7. 7.What is ∛2744? =
  8. 8.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  9. 9.What is 11³? =
  10. 10.What is 10³? =
  11. 11.Which of these is a perfect cube? (a) 3967 (b) 3703 (c) 3375
  12. 12.What is ∛512? =
  13. 13.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  14. 14.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  15. 15.What is ∛3375? =
  16. 16.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  17. 17.Which of these is a perfect cube? (a) 260 (b) 216 (c) 284
  18. 18.What is ∛15625? =
  19. 19.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  20. 20.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  21. 21.What is ∛9261? =
  22. 22.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  23. 23.What is ∛216? =
  24. 24.What is 20³? =
  25. 25.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  26. 26.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  27. 27.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  28. 28.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  29. 29.What is 19³? =
  30. 30.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  31. 31.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 408 (b) 384 (c) 343
  33. 33.What is 5³? =
  34. 34.What is ∛729? =
  35. 35.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  36. 36.What is the smallest whole number by which 200 must be divided to get a perfect cube?
  37. 37.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  38. 38.Which of these is a perfect cube? (a) 50 (b) 27 (c) 49
  39. 39.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  40. 40.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?

Answer key

  1. 18
  2. 216
  3. 2
  4. 49
  5. 12
  6. 8
  7. 14
  8. 125
  9. 1331
  10. 1000
  11. 3375
  12. 8
  13. 25
  14. 27
  15. 15
  16. 8
  17. 216
  18. 25
  19. 2
  20. 3
  21. 21
  22. 64
  23. 6
  24. 8000
  25. 64
  26. 2
  27. 9
  28. 13
  29. 6859
  30. 125
  31. 8
  32. 343
  33. 125
  34. 9
  35. 4
  36. 25
  37. 3
  38. 27
  39. 64
  40. 2

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