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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 739 · 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 ∛3375? =
  2. 2.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  3. 3.What is ∛12167? =
  4. 4.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  5. 5.What is 8³? =
  6. 6.Which of these is a perfect cube? (a) 125 (b) 142 (c) 188
  7. 7.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  8. 8.What is ∛27? =
  9. 9.What is ∛125? =
  10. 10.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  11. 11.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
  12. 12.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  13. 13.What is ∛512? =
  14. 14.What is ∛64? =
  15. 15.What is ∛9261? =
  16. 16.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  17. 17.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  18. 18.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  19. 19.What is 18³? =
  20. 20.What is 7³? =
  21. 21.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  22. 22.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  23. 23.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  24. 24.What is ∛1000? =
  25. 25.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  26. 26.What is ∛8? =
  27. 27.Which of these is a perfect cube? (a) 343 (b) 368 (c) 362
  28. 28.What is ∛1728? =
  29. 29.Which of these is a perfect cube? (a) 1410 (b) 1549 (c) 1331
  30. 30.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  31. 31.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 1278 (b) 1164 (c) 1000
  33. 33.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  34. 34.What is ∛6859? =
  35. 35.Which of these is a perfect cube? (a) 2805 (b) 2961 (c) 2744
  36. 36.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  37. 37.What is 4³? =
  38. 38.What is ∛10648? =
  39. 39.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  40. 40.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?

Answer key

  1. 15
  2. 216
  3. 23
  4. 8
  5. 512
  6. 125
  7. 64
  8. 3
  9. 5
  10. 4
  11. 49
  12. 19
  13. 8
  14. 4
  15. 21
  16. 15
  17. 125
  18. 4
  19. 5832
  20. 343
  21. 64
  22. 27
  23. 17
  24. 10
  25. 8
  26. 2
  27. 343
  28. 12
  29. 1331
  30. 12
  31. 216
  32. 1000
  33. 5
  34. 19
  35. 2744
  36. 14
  37. 64
  38. 22
  39. 7
  40. 216

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