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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 951 · 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.Which of these is a perfect cube? (a) 343 (b) 364 (c) 349
  2. 2.What is 2³? =
  3. 3.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  4. 4.Which of these is a perfect cube? (a) 27 (b) 37 (c) 54
  5. 5.What is 11³? =
  6. 6.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  7. 7.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  8. 8.What is ∛5832? =
  9. 9.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  10. 10.What is 12³? =
  11. 11.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  12. 12.What is the smallest whole number by which 5 must be divided to get a perfect cube?
  13. 13.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  14. 14.What is ∛3375? =
  15. 15.What is the smallest whole number by which 675 must be multiplied to get a perfect cube?
  16. 16.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  17. 17.Which of these is a perfect cube? (a) 729 (b) 875 (c) 889
  18. 18.Which of these is a perfect cube? (a) 1652 (b) 1331 (c) 1593
  19. 19.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  20. 20.Which of these is a perfect cube? (a) 3788 (b) 3593 (c) 3375
  21. 21.What is the smallest whole number by which 81 must be divided to get a perfect cube?
  22. 22.What is ∛8000? =
  23. 23.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
  24. 24.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  25. 25.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  26. 26.What is ∛343? =
  27. 27.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  28. 28.What is 17³? =
  29. 29.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  30. 30.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  31. 31.Which of these is a perfect cube? (a) 65 (b) 64 (c) 88
  32. 32.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  33. 33.What is 5³? =
  34. 34.What is ∛10648? =
  35. 35.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  36. 36.What is 4³? =
  37. 37.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  38. 38.Which of these is a perfect cube? (a) 291 (b) 275 (c) 216
  39. 39.Which of these is a perfect cube? (a) 2899 (b) 2832 (c) 2744
  40. 40.Which of these is a perfect cube? (a) 602 (b) 529 (c) 512

Answer key

  1. 343
  2. 8
  3. 9
  4. 27
  5. 1331
  6. 5
  7. 10
  8. 18
  9. 25
  10. 1728
  11. 27
  12. 5
  13. 18
  14. 15
  15. 5
  16. 125
  17. 729
  18. 1331
  19. 5
  20. 3375
  21. 3
  22. 20
  23. 3
  24. 16
  25. 3
  26. 7
  27. 19
  28. 4913
  29. 2
  30. 5
  31. 64
  32. 64
  33. 125
  34. 22
  35. 8
  36. 64
  37. 2
  38. 216
  39. 2744
  40. 512

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