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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 767 · 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 the smallest whole number by which 1600 must be divided to get a perfect cube?
  2. 2.What is 11³? =
  3. 3.What is 14³? =
  4. 4.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  5. 5.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  6. 6.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  7. 7.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  8. 8.What is ∛27? =
  9. 9.What is ∛729? =
  10. 10.What is 8³? =
  11. 11.Which of these is a perfect cube? (a) 1911 (b) 1728 (c) 1806
  12. 12.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  13. 13.Which of these is a perfect cube? (a) 3247 (b) 2823 (c) 2744
  14. 14.What is 19³? =
  15. 15.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  16. 16.What is 10³? =
  17. 17.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  18. 18.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  19. 19.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  20. 20.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  21. 21.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  22. 22.What is ∛1000? =
  23. 23.What is 12³? =
  24. 24.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  25. 25.What is 5³? =
  26. 26.What is the smallest whole number by which 5400 must be divided to get a perfect cube?
  27. 27.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  28. 28.What is ∛512? =
  29. 29.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  30. 30.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  31. 31.What is ∛8? =
  32. 32.What is ∛4096? =
  33. 33.What is 2³? =
  34. 34.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  35. 35.Which of these is a perfect cube? (a) 457 (b) 348 (c) 343
  36. 36.What is 9³? =
  37. 37.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  38. 38.Which of these is a perfect cube? (a) 1292 (b) 1011 (c) 1000
  39. 39.Which of these is a perfect cube? (a) 27 (b) 47 (c) 31
  40. 40.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?

Answer key

  1. 25
  2. 1331
  3. 2744
  4. 18
  5. 2
  6. 8
  7. 7
  8. 3
  9. 9
  10. 512
  11. 1728
  12. 3
  13. 2744
  14. 6859
  15. 25
  16. 1000
  17. 8
  18. 27
  19. 27
  20. 2
  21. 125
  22. 10
  23. 1728
  24. 49
  25. 125
  26. 25
  27. 27
  28. 8
  29. 125
  30. 16
  31. 2
  32. 16
  33. 8
  34. 64
  35. 343
  36. 729
  37. 64
  38. 1000
  39. 27
  40. 11

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