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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 400 · 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 6³? =
  2. 2.What is 15³? =
  3. 3.What is 12³? =
  4. 4.Which of these is a perfect cube? (a) 1660 (b) 1683 (c) 1331
  5. 5.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  7. 7.What is 5³? =
  8. 8.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  9. 9.What is ∛729? =
  10. 10.What is ∛3375? =
  11. 11.Which of these is a perfect cube? (a) 1190 (b) 1117 (c) 1000
  12. 12.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  13. 13.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  14. 14.Which of these is a perfect cube? (a) 31 (b) 27 (c) 32
  15. 15.What is ∛1000? =
  16. 16.What is 7³? =
  17. 17.What is 9³? =
  18. 18.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  19. 19.A big cube of edge 24 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 3 must be multiplied to get a perfect cube?
  21. 21.Which of these is a perfect cube? (a) 306 (b) 216 (c) 223
  22. 22.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  23. 23.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  24. 24.What is 16³? =
  25. 25.What is ∛4096? =
  26. 26.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  27. 27.What is 17³? =
  28. 28.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  29. 29.What is ∛2197? =
  30. 30.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
  31. 31.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  32. 32.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  33. 33.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  34. 34.Which of these is a perfect cube? (a) 77 (b) 108 (c) 64
  35. 35.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  36. 36.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  37. 37.What is ∛6859? =
  38. 38.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  39. 39.Which of these is a perfect cube? (a) 377 (b) 361 (c) 343
  40. 40.What is 10³? =

Answer key

  1. 216
  2. 3375
  3. 1728
  4. 1331
  5. 64
  6. 8
  7. 125
  8. 27
  9. 9
  10. 15
  11. 1000
  12. 64
  13. 17
  14. 27
  15. 10
  16. 343
  17. 729
  18. 8
  19. 216
  20. 9
  21. 216
  22. 20
  23. 3
  24. 4096
  25. 16
  26. 6
  27. 4913
  28. 12
  29. 13
  30. 3
  31. 3
  32. 4
  33. 49
  34. 64
  35. 14
  36. 2
  37. 19
  38. 11
  39. 343
  40. 1000

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