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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 934 · 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 the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  2. 2.Which of these is a perfect cube? (a) 1331 (b) 1541 (c) 1618
  3. 3.What is 11³? =
  4. 4.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  5. 5.What is 13³? =
  6. 6.What is 6³? =
  7. 7.Which of these is a perfect cube? (a) 2197 (b) 2477 (c) 2246
  8. 8.What is 15³? =
  9. 9.What is 17³? =
  10. 10.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  11. 11.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  12. 12.What is ∛13824? =
  13. 13.What is 7³? =
  14. 14.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  15. 15.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?
  16. 16.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  17. 17.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  18. 18.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  19. 19.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  20. 20.What is ∛125? =
  21. 21.Which of these is a perfect cube? (a) 1943 (b) 2100 (c) 1728
  22. 22.What is ∛729? =
  23. 23.What is 2³? =
  24. 24.What is 10³? =
  25. 25.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  26. 26.What is the smallest whole number by which 256 must be divided to get a perfect cube?
  27. 27.What is the smallest whole number by which 648 must be multiplied to get a perfect cube?
  28. 28.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  29. 29.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  30. 30.What is ∛6859? =
  31. 31.What is ∛10648? =
  32. 32.Which of these is a perfect cube? (a) 27 (b) 28 (c) 47
  33. 33.What is ∛1728? =
  34. 34.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  35. 35.What is the smallest whole number by which 250 must be multiplied to get a perfect cube?
  36. 36.What is 4³? =
  37. 37.What is ∛4913? =
  38. 38.What is 16³? =
  39. 39.What is ∛64? =
  40. 40.What is ∛3375? =

Answer key

  1. 5
  2. 1331
  3. 1331
  4. 2
  5. 2197
  6. 216
  7. 2197
  8. 3375
  9. 4913
  10. 11
  11. 6
  12. 24
  13. 343
  14. 4
  15. 7
  16. 8
  17. 3
  18. 15
  19. 64
  20. 5
  21. 1728
  22. 9
  23. 8
  24. 1000
  25. 18
  26. 4
  27. 9
  28. 3
  29. 125
  30. 19
  31. 22
  32. 27
  33. 12
  34. 27
  35. 4
  36. 64
  37. 17
  38. 4096
  39. 4
  40. 15

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