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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 802 · 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) 1226 (b) 1050 (c) 1000
  2. 2.Which of these is a perfect cube? (a) 2046 (b) 2123 (c) 1728
  3. 3.What is the smallest whole number by which 256 must be divided to get a perfect cube?
  4. 4.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  5. 5.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  6. 6.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  7. 7.What is ∛13824? =
  8. 8.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  9. 9.What is 9³? =
  10. 10.What is the smallest whole number by which 448 must be multiplied to get a perfect cube?
  11. 11.What is 14³? =
  12. 12.What is ∛1000? =
  13. 13.What is 13³? =
  14. 14.What is the smallest whole number by which 500 must be divided to get a perfect cube?
  15. 15.Which of these is a perfect cube? (a) 819 (b) 777 (c) 729
  16. 16.What is ∛512? =
  17. 17.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  18. 18.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  19. 19.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  20. 20.What is the smallest whole number by which 3125 must be divided to get a perfect cube?
  21. 21.What is the smallest whole number by which 24 must be divided to get a perfect cube?
  22. 22.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?
  23. 23.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
  24. 24.Which of these is a perfect cube? (a) 71 (b) 75 (c) 64
  25. 25.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  26. 26.Which of these is a perfect cube? (a) 3920 (b) 3375 (c) 3448
  27. 27.What is ∛9261? =
  28. 28.What is ∛125? =
  29. 29.What is ∛27? =
  30. 30.What is 8³? =
  31. 31.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  32. 32.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  33. 33.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  34. 34.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  35. 35.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  36. 36.What is 3³? =
  37. 37.What is ∛15625? =
  38. 38.Which of these is a perfect cube? (a) 155 (b) 125 (c) 140
  39. 39.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  40. 40.What is 18³? =

Answer key

  1. 1000
  2. 1728
  3. 4
  4. 125
  5. 2
  6. 9
  7. 24
  8. 8
  9. 729
  10. 49
  11. 2744
  12. 10
  13. 2197
  14. 4
  15. 729
  16. 8
  17. 27
  18. 16
  19. 8
  20. 25
  21. 3
  22. 7
  23. 7
  24. 64
  25. 17
  26. 3375
  27. 21
  28. 5
  29. 3
  30. 512
  31. 216
  32. 14
  33. 64
  34. 49
  35. 2
  36. 27
  37. 25
  38. 125
  39. 12
  40. 5832

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