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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 912 · 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 ∛8000? =
  2. 2.What is ∛5832? =
  3. 3.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  4. 4.What is the smallest whole number by which 3125 must be divided to get a perfect cube?
  5. 5.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  6. 6.What is 12³? =
  7. 7.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  8. 8.What is ∛8? =
  9. 9.Which of these is a perfect cube? (a) 1331 (b) 1521 (c) 1459
  10. 10.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  11. 11.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  12. 12.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  13. 13.What is 11³? =
  14. 14.What is ∛512? =
  15. 15.Which of these is a perfect cube? (a) 125 (b) 157 (c) 166
  16. 16.What is ∛4913? =
  17. 17.What is 2³? =
  18. 18.What is ∛4096? =
  19. 19.Which of these is a perfect cube? (a) 3375 (b) 3601 (c) 3688
  20. 20.What is 15³? =
  21. 21.Which of these is a perfect cube? (a) 371 (b) 343 (c) 429
  22. 22.What is ∛729? =
  23. 23.What is 14³? =
  24. 24.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  25. 25.Which of these is a perfect cube? (a) 112 (b) 76 (c) 64
  26. 26.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  27. 27.What is 18³? =
  28. 28.What is 7³? =
  29. 29.Which of these is a perfect cube? (a) 30 (b) 27 (c) 36
  30. 30.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  31. 31.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 1728 (b) 1779 (c) 1796
  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.What is 17³? =
  35. 35.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  36. 36.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  37. 37.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  38. 38.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?
  39. 39.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  40. 40.What is 9³? =

Answer key

  1. 20
  2. 18
  3. 5
  4. 25
  5. 11
  6. 1728
  7. 5
  8. 2
  9. 1331
  10. 14
  11. 3
  12. 125
  13. 1331
  14. 8
  15. 125
  16. 17
  17. 8
  18. 16
  19. 3375
  20. 3375
  21. 343
  22. 9
  23. 2744
  24. 17
  25. 64
  26. 7
  27. 5832
  28. 343
  29. 27
  30. 216
  31. 8
  32. 1728
  33. 8
  34. 4913
  35. 3
  36. 16
  37. 8
  38. 7
  39. 8
  40. 729

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