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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 566 · 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 11³? =
  2. 2.What is 19³? =
  3. 3.What is 2³? =
  4. 4.Which of these is a perfect cube? (a) 242 (b) 216 (c) 224
  5. 5.What is 5³? =
  6. 6.What is ∛3375? =
  7. 7.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  8. 8.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  9. 9.Which of these is a perfect cube? (a) 2026 (b) 1728 (c) 1935
  10. 10.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  11. 11.What is 7³? =
  12. 12.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  13. 13.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  14. 14.What is ∛2197? =
  15. 15.What is 12³? =
  16. 16.What is 14³? =
  17. 17.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  18. 18.What is ∛216? =
  19. 19.What is ∛343? =
  20. 20.What is 10³? =
  21. 21.What is ∛1000? =
  22. 22.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  23. 23.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  24. 24.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  25. 25.What is ∛512? =
  26. 26.What is ∛9261? =
  27. 27.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  28. 28.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  29. 29.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  30. 30.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  31. 31.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  32. 32.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  33. 33.What is 16³? =
  34. 34.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  35. 35.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  36. 36.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
  37. 37.What is ∛64? =
  38. 38.What is the smallest whole number by which 256 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 ∛729? =

Answer key

  1. 1331
  2. 6859
  3. 8
  4. 216
  5. 125
  6. 15
  7. 27
  8. 49
  9. 1728
  10. 8
  11. 343
  12. 125
  13. 3
  14. 13
  15. 1728
  16. 2744
  17. 64
  18. 6
  19. 7
  20. 1000
  21. 10
  22. 8
  23. 14
  24. 9
  25. 8
  26. 21
  27. 11
  28. 216
  29. 216
  30. 2
  31. 3
  32. 6
  33. 4096
  34. 27
  35. 8
  36. 49
  37. 4
  38. 2
  39. 8
  40. 9

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