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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 324 · 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 9 must be divided to get a perfect cube?
  2. 2.What is ∛1728? =
  3. 3.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  4. 4.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  5. 5.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  7. 7.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  8. 8.Which of these is a perfect cube? (a) 512 (b) 529 (c) 703
  9. 9.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  10. 10.Which of these is a perfect cube? (a) 178 (b) 163 (c) 125
  11. 11.What is 7³? =
  12. 12.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  13. 13.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  14. 14.What is ∛1000? =
  15. 15.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  16. 16.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
  17. 17.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
  18. 18.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  19. 19.What is 3³? =
  20. 20.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  21. 21.What is ∛12167? =
  22. 22.What is 13³? =
  23. 23.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  24. 24.What is ∛512? =
  25. 25.Which of these is a perfect cube? (a) 387 (b) 414 (c) 343
  26. 26.What is ∛9261? =
  27. 27.What is 4³? =
  28. 28.Which of these is a perfect cube? (a) 50 (b) 39 (c) 27
  29. 29.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  30. 30.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
  31. 31.What is 9³? =
  32. 32.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  33. 33.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  34. 34.Which of these is a perfect cube? (a) 729 (b) 959 (c) 951
  35. 35.What is ∛4913? =
  36. 36.What is 14³? =
  37. 37.What is ∛2744? =
  38. 38.What is 17³? =
  39. 39.What is ∛1331? =
  40. 40.What is ∛5832? =

Answer key

  1. 9
  2. 12
  3. 3
  4. 216
  5. 125
  6. 49
  7. 5
  8. 512
  9. 216
  10. 125
  11. 343
  12. 25
  13. 4
  14. 10
  15. 14
  16. 49
  17. 49
  18. 19
  19. 27
  20. 20
  21. 23
  22. 2197
  23. 25
  24. 8
  25. 343
  26. 21
  27. 64
  28. 27
  29. 64
  30. 9
  31. 729
  32. 216
  33. 10
  34. 729
  35. 17
  36. 2744
  37. 14
  38. 4913
  39. 11
  40. 18

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