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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 918 · 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 3³? =
  2. 2.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  3. 3.What is 8³? =
  4. 4.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  5. 5.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  6. 6.What is ∛2744? =
  7. 7.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  8. 8.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  9. 9.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  11. 11.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  12. 12.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  13. 13.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  14. 14.What is 18³? =
  15. 15.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  16. 16.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  17. 17.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  18. 18.What is 10³? =
  19. 19.What is ∛343? =
  20. 20.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
  21. 21.What is ∛27? =
  22. 22.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  23. 23.Which of these is a perfect cube? (a) 4039 (b) 3443 (c) 3375
  24. 24.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  25. 25.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
  26. 26.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  27. 27.What is ∛12167? =
  28. 28.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  29. 29.What is ∛512? =
  30. 30.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
  31. 31.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  32. 32.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  33. 33.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  34. 34.What is the smallest whole number by which 81 must be divided to get a perfect cube?
  35. 35.What is 7³? =
  36. 36.What is ∛15625? =
  37. 37.Which of these is a perfect cube? (a) 348 (b) 343 (c) 347
  38. 38.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  39. 39.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  40. 40.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?

Answer key

  1. 27
  2. 7
  3. 512
  4. 19
  5. 8
  6. 14
  7. 10
  8. 9
  9. 125
  10. 27
  11. 2
  12. 9
  13. 4
  14. 5832
  15. 3
  16. 14
  17. 27
  18. 1000
  19. 7
  20. 9
  21. 3
  22. 49
  23. 3375
  24. 5
  25. 2
  26. 18
  27. 23
  28. 216
  29. 8
  30. 49
  31. 64
  32. 3
  33. 49
  34. 3
  35. 343
  36. 25
  37. 343
  38. 8
  39. 125
  40. 9

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