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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 762 · 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 7³? =
  2. 2.What is ∛8000? =
  3. 3.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  4. 4.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  5. 5.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.What is ∛64? =
  7. 7.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  8. 8.What is 4³? =
  9. 9.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  10. 10.What is 2³? =
  11. 11.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
  12. 12.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  13. 13.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  14. 14.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  15. 15.Which of these is a perfect cube? (a) 1799 (b) 1728 (c) 2100
  16. 16.What is 17³? =
  17. 17.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  18. 18.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  19. 19.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  20. 20.Which of these is a perfect cube? (a) 111 (b) 82 (c) 64
  21. 21.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  22. 22.What is 18³? =
  23. 23.What is 8³? =
  24. 24.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  25. 25.Which of these is a perfect cube? (a) 3533 (b) 3375 (c) 3520
  26. 26.What is 5³? =
  27. 27.What is ∛729? =
  28. 28.What is ∛125? =
  29. 29.What is ∛1000? =
  30. 30.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  31. 31.What is 3³? =
  32. 32.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  33. 33.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  34. 34.What is 9³? =
  35. 35.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  36. 36.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  37. 37.What is the smallest whole number by which 135 must be divided to get a perfect cube?
  38. 38.What is ∛4096? =
  39. 39.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  40. 40.What is 12³? =

Answer key

  1. 343
  2. 20
  3. 27
  4. 125
  5. 8
  6. 4
  7. 13
  8. 64
  9. 20
  10. 8
  11. 2
  12. 2
  13. 125
  14. 4
  15. 1728
  16. 4913
  17. 10
  18. 7
  19. 9
  20. 64
  21. 64
  22. 5832
  23. 512
  24. 64
  25. 3375
  26. 125
  27. 9
  28. 5
  29. 10
  30. 27
  31. 27
  32. 7
  33. 49
  34. 729
  35. 8
  36. 12
  37. 5
  38. 16
  39. 2
  40. 1728

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