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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 871 · 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 ∛1000? =
  2. 2.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  3. 3.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  4. 4.What is ∛3375? =
  5. 5.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  6. 6.What is ∛27? =
  7. 7.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  8. 8.What is 19³? =
  9. 9.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  10. 10.Which of these is a perfect cube? (a) 195 (b) 165 (c) 125
  11. 11.What is ∛1331? =
  12. 12.What is 15³? =
  13. 13.What is ∛5832? =
  14. 14.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  15. 15.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  16. 16.What is 17³? =
  17. 17.Which of these is a perfect cube? (a) 343 (b) 375 (c) 433
  18. 18.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  19. 19.Which of these is a perfect cube? (a) 1000 (b) 1150 (c) 1096
  20. 20.What is the smallest whole number by which 3136 must be divided to get a perfect cube?
  21. 21.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?
  22. 22.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  23. 23.Which of these is a perfect cube? (a) 2197 (b) 2551 (c) 2308
  24. 24.What is 2³? =
  25. 25.What is 18³? =
  26. 26.What is 7³? =
  27. 27.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
  28. 28.Which of these is a perfect cube? (a) 64 (b) 108 (c) 98
  29. 29.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  30. 30.What is 10³? =
  31. 31.What is 16³? =
  32. 32.What is 12³? =
  33. 33.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  34. 34.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  35. 35.Which of these is a perfect cube? (a) 1736 (b) 1728 (c) 1966
  36. 36.What is 4³? =
  37. 37.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  38. 38.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  39. 39.What is ∛15625? =
  40. 40.What is 6³? =

Answer key

  1. 10
  2. 5
  3. 5
  4. 15
  5. 12
  6. 3
  7. 13
  8. 6859
  9. 125
  10. 125
  11. 11
  12. 3375
  13. 18
  14. 125
  15. 7
  16. 4913
  17. 343
  18. 5
  19. 1000
  20. 49
  21. 7
  22. 6
  23. 2197
  24. 8
  25. 5832
  26. 343
  27. 49
  28. 64
  29. 9
  30. 1000
  31. 4096
  32. 1728
  33. 8
  34. 27
  35. 1728
  36. 64
  37. 2
  38. 14
  39. 25
  40. 216

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