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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 213 · 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) 882 (b) 729 (c) 757
  2. 2.What is ∛13824? =
  3. 3.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  4. 4.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?
  5. 5.Which of these is a perfect cube? (a) 3424 (b) 3918 (c) 3375
  6. 6.What is 12³? =
  7. 7.What is ∛15625? =
  8. 8.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  9. 9.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  10. 10.What is ∛1728? =
  11. 11.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  12. 12.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  13. 13.Which of these is a perfect cube? (a) 125 (b) 155 (c) 132
  14. 14.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  15. 15.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  16. 16.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  17. 17.What is 8³? =
  18. 18.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
  19. 19.What is 9³? =
  20. 20.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  21. 21.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  22. 22.What is 10³? =
  23. 23.Which of these is a perfect cube? (a) 64 (b) 75 (c) 91
  24. 24.Which of these is a perfect cube? (a) 641 (b) 659 (c) 512
  25. 25.Which of these is a perfect cube? (a) 2356 (b) 2593 (c) 2197
  26. 26.What is ∛2197? =
  27. 27.What is ∛729? =
  28. 28.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  29. 29.Which of these is a perfect cube? (a) 2744 (b) 2818 (c) 3302
  30. 30.What is ∛343? =
  31. 31.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  32. 32.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  33. 33.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  34. 34.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  35. 35.Which of these is a perfect cube? (a) 1903 (b) 1728 (c) 1982
  36. 36.What is 20³? =
  37. 37.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  38. 38.Which of these is a perfect cube? (a) 27 (b) 48 (c) 36
  39. 39.Which of these is a perfect cube? (a) 1258 (b) 1236 (c) 1000
  40. 40.What is 17³? =

Answer key

  1. 729
  2. 24
  3. 64
  4. 7
  5. 3375
  6. 1728
  7. 25
  8. 8
  9. 2
  10. 12
  11. 2
  12. 4
  13. 125
  14. 4
  15. 125
  16. 64
  17. 512
  18. 49
  19. 729
  20. 13
  21. 12
  22. 1000
  23. 64
  24. 512
  25. 2197
  26. 13
  27. 9
  28. 20
  29. 2744
  30. 7
  31. 2
  32. 27
  33. 7
  34. 27
  35. 1728
  36. 8000
  37. 4
  38. 27
  39. 1000
  40. 4913

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