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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 100 · 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 big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  2. 2.What is 12³? =
  3. 3.Which of these is a perfect cube? (a) 125 (b) 134 (c) 177
  4. 4.Which of these is a perfect cube? (a) 1000 (b) 1277 (c) 1252
  5. 5.What is ∛1000? =
  6. 6.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  7. 7.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  8. 8.What is the smallest whole number by which 243 must be multiplied to get a perfect cube?
  9. 9.What is 5³? =
  10. 10.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  11. 11.What is 2³? =
  12. 12.What is ∛15625? =
  13. 13.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  14. 14.Which of these is a perfect cube? (a) 3575 (b) 3375 (c) 3376
  15. 15.What is the smallest whole number by which 5 must be divided to get a perfect cube?
  16. 16.Which of these is a perfect cube? (a) 457 (b) 343 (c) 442
  17. 17.Which of these is a perfect cube? (a) 894 (b) 729 (c) 945
  18. 18.What is 11³? =
  19. 19.What is ∛9261? =
  20. 20.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  21. 21.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  22. 22.Which of these is a perfect cube? (a) 72 (b) 109 (c) 64
  23. 23.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  24. 24.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  25. 25.What is 19³? =
  26. 26.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
  27. 27.What is ∛729? =
  28. 28.Which of these is a perfect cube? (a) 512 (b) 634 (c) 616
  29. 29.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  30. 30.What is ∛125? =
  31. 31.A big cube of edge 20 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) 3084 (b) 2880 (c) 2744
  33. 33.What is the smallest whole number by which 675 must be multiplied to get a perfect cube?
  34. 34.What is 8³? =
  35. 35.What is ∛4913? =
  36. 36.Which of these is a perfect cube? (a) 1785 (b) 1728 (c) 2049
  37. 37.What is 6³? =
  38. 38.What is ∛10648? =
  39. 39.What is ∛343? =
  40. 40.What is ∛64? =

Answer key

  1. 8
  2. 1728
  3. 125
  4. 1000
  5. 10
  6. 2
  7. 3
  8. 3
  9. 125
  10. 7
  11. 8
  12. 25
  13. 7
  14. 3375
  15. 5
  16. 343
  17. 729
  18. 1331
  19. 21
  20. 64
  21. 5
  22. 64
  23. 2
  24. 12
  25. 6859
  26. 49
  27. 9
  28. 512
  29. 5
  30. 5
  31. 125
  32. 2744
  33. 5
  34. 512
  35. 17
  36. 1728
  37. 216
  38. 22
  39. 7
  40. 4

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