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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 977 · 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 cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  2. 2.What is ∛8000? =
  3. 3.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  4. 4.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  5. 5.What is the smallest whole number by which 135 must be multiplied to get a perfect cube?
  6. 6.What is ∛4096? =
  7. 7.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  8. 8.What is 17³? =
  9. 9.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  10. 10.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  11. 11.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  12. 12.Which of these is a perfect cube? (a) 2131 (b) 1728 (c) 1775
  13. 13.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  14. 14.What is ∛3375? =
  15. 15.What is the smallest whole number by which 1512 must be divided to get a perfect cube?
  16. 16.What is ∛8? =
  17. 17.What is ∛15625? =
  18. 18.What is 18³? =
  19. 19.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  20. 20.Which of these is a perfect cube? (a) 216 (b) 230 (c) 311
  21. 21.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  22. 22.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  23. 23.What is ∛216? =
  24. 24.Which of these is a perfect cube? (a) 1363 (b) 1679 (c) 1331
  25. 25.What is ∛1000? =
  26. 26.Which of these is a perfect cube? (a) 2254 (b) 2197 (c) 2636
  27. 27.Which of these is a perfect cube? (a) 402 (b) 343 (c) 344
  28. 28.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  29. 29.What is the smallest whole number by which 5400 must be divided to get a perfect cube?
  30. 30.Which of these is a perfect cube? (a) 91 (b) 69 (c) 64
  31. 31.What is ∛5832? =
  32. 32.What is ∛343? =
  33. 33.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  34. 34.Which of these is a perfect cube? (a) 3375 (b) 3659 (c) 3531
  35. 35.What is ∛10648? =
  36. 36.What is the smallest whole number by which 250 must be divided to get a perfect cube?
  37. 37.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  38. 38.What is 7³? =
  39. 39.What is ∛1331? =
  40. 40.What is 16³? =

Answer key

  1. 9
  2. 20
  3. 19
  4. 49
  5. 25
  6. 16
  7. 3
  8. 4913
  9. 64
  10. 5
  11. 16
  12. 1728
  13. 125
  14. 15
  15. 7
  16. 2
  17. 25
  18. 5832
  19. 3
  20. 216
  21. 125
  22. 8
  23. 6
  24. 1331
  25. 10
  26. 2197
  27. 343
  28. 27
  29. 25
  30. 64
  31. 18
  32. 7
  33. 9
  34. 3375
  35. 22
  36. 2
  37. 15
  38. 343
  39. 11
  40. 4096

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