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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 80 · 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 ∛2197? =
  2. 2.Which of these is a perfect cube? (a) 75 (b) 64 (c) 108
  3. 3.What is ∛4913? =
  4. 4.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  5. 5.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.What is 9³? =
  7. 7.What is 10³? =
  8. 8.What is 6³? =
  9. 9.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  10. 10.What is 12³? =
  11. 11.What is 4³? =
  12. 12.What is ∛1728? =
  13. 13.Which of these is a perfect cube? (a) 52 (b) 27 (c) 28
  14. 14.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  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.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  17. 17.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  18. 18.What is ∛125? =
  19. 19.Which of these is a perfect cube? (a) 3081 (b) 2757 (c) 2744
  20. 20.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  21. 21.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  22. 22.What is 18³? =
  23. 23.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  24. 24.What is 7³? =
  25. 25.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  26. 26.Which of these is a perfect cube? (a) 483 (b) 475 (c) 343
  27. 27.What is 15³? =
  28. 28.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  29. 29.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  30. 30.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  31. 31.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  32. 32.What is ∛1000? =
  33. 33.Which of these is a perfect cube? (a) 278 (b) 293 (c) 216
  34. 34.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  35. 35.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  36. 36.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  37. 37.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  38. 38.A big cube of edge 8 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 24 must be divided to get a perfect cube?
  40. 40.Which of these is a perfect cube? (a) 647 (b) 512 (c) 546

Answer key

  1. 13
  2. 64
  3. 17
  4. 5
  5. 125
  6. 729
  7. 1000
  8. 216
  9. 216
  10. 1728
  11. 64
  12. 12
  13. 27
  14. 49
  15. 216
  16. 49
  17. 64
  18. 5
  19. 2744
  20. 9
  21. 27
  22. 5832
  23. 3
  24. 343
  25. 8
  26. 343
  27. 3375
  28. 49
  29. 17
  30. 216
  31. 49
  32. 10
  33. 216
  34. 4
  35. 125
  36. 3
  37. 19
  38. 64
  39. 3
  40. 512

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