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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 902 · 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 2³? =
  2. 2.Which of these is a perfect cube? (a) 247 (b) 270 (c) 216
  3. 3.What is 19³? =
  4. 4.What is ∛4096? =
  5. 5.What is ∛8000? =
  6. 6.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  7. 7.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  8. 8.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  9. 9.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  10. 10.What is ∛5832? =
  11. 11.What is 5³? =
  12. 12.What is 7³? =
  13. 13.What is ∛15625? =
  14. 14.What is ∛4913? =
  15. 15.What is 14³? =
  16. 16.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
  17. 17.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  18. 18.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  19. 19.What is the smallest whole number by which 675 must be multiplied to get a perfect cube?
  20. 20.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  21. 21.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  22. 22.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
  23. 23.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
  24. 24.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  25. 25.What is 6³? =
  26. 26.What is ∛1000? =
  27. 27.What is 10³? =
  28. 28.What is 11³? =
  29. 29.What is ∛3375? =
  30. 30.What is 3³? =
  31. 31.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 735 (b) 792 (c) 729
  33. 33.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  34. 34.What is 18³? =
  35. 35.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  36. 36.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  37. 37.What is ∛12167? =
  38. 38.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  39. 39.What is 16³? =
  40. 40.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?

Answer key

  1. 8
  2. 216
  3. 6859
  4. 16
  5. 20
  6. 20
  7. 216
  8. 11
  9. 3
  10. 18
  11. 125
  12. 343
  13. 25
  14. 17
  15. 2744
  16. 3
  17. 27
  18. 49
  19. 5
  20. 2
  21. 64
  22. 4
  23. 49
  24. 8
  25. 216
  26. 10
  27. 1000
  28. 1331
  29. 15
  30. 27
  31. 27
  32. 729
  33. 14
  34. 5832
  35. 25
  36. 49
  37. 23
  38. 2
  39. 4096
  40. 9

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