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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 856 · 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 5³? =
  2. 2.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  3. 3.What is ∛729? =
  4. 4.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
  5. 5.What is ∛12167? =
  6. 6.What is ∛2744? =
  7. 7.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  8. 8.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  9. 9.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  10. 10.Which of these is a perfect cube? (a) 512 (b) 694 (c) 601
  11. 11.What is ∛125? =
  12. 12.What is 20³? =
  13. 13.Which of these is a perfect cube? (a) 1421 (b) 1331 (c) 1492
  14. 14.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  15. 15.What is ∛3375? =
  16. 16.Which of these is a perfect cube? (a) 2446 (b) 2197 (c) 2440
  17. 17.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  18. 18.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  19. 19.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  20. 20.What is 19³? =
  21. 21.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  22. 22.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  23. 23.What is ∛9261? =
  24. 24.Which of these is a perfect cube? (a) 185 (b) 125 (c) 162
  25. 25.What is 2³? =
  26. 26.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  27. 27.What is 16³? =
  28. 28.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  29. 29.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  30. 30.Which of these is a perfect cube? (a) 225 (b) 307 (c) 216
  31. 31.Which of these is a perfect cube? (a) 52 (b) 51 (c) 27
  32. 32.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  33. 33.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  34. 34.What is ∛2197? =
  35. 35.What is ∛4096? =
  36. 36.Which of these is a perfect cube? (a) 384 (b) 343 (c) 405
  37. 37.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  38. 38.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  39. 39.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  40. 40.What is ∛6859? =

Answer key

  1. 125
  2. 9
  3. 9
  4. 49
  5. 23
  6. 14
  7. 3
  8. 4
  9. 11
  10. 512
  11. 5
  12. 8000
  13. 1331
  14. 125
  15. 15
  16. 2197
  17. 5
  18. 13
  19. 125
  20. 6859
  21. 8
  22. 14
  23. 21
  24. 125
  25. 8
  26. 4
  27. 4096
  28. 8
  29. 216
  30. 216
  31. 27
  32. 16
  33. 20
  34. 13
  35. 16
  36. 343
  37. 15
  38. 216
  39. 4
  40. 19

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