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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 268 · 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) 196 (b) 125 (c) 169
  2. 2.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  3. 3.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  4. 4.What is ∛8? =
  5. 5.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
  6. 6.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  7. 7.What is the smallest whole number by which 25 must be divided to get a perfect cube?
  8. 8.What is ∛64? =
  9. 9.Which of these is a perfect cube? (a) 27 (b) 36 (c) 31
  10. 10.What is the smallest whole number by which 500 must be multiplied to get a perfect cube?
  11. 11.Which of these is a perfect cube? (a) 1413 (b) 1331 (c) 1603
  12. 12.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  13. 13.Which of these is a perfect cube? (a) 2235 (b) 2671 (c) 2197
  14. 14.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  15. 15.What is 11³? =
  16. 16.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  17. 17.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  18. 18.What is 20³? =
  19. 19.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  20. 20.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  21. 21.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  22. 22.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  23. 23.What is ∛4913? =
  24. 24.What is 9³? =
  25. 25.What is ∛27? =
  26. 26.What is ∛729? =
  27. 27.Which of these is a perfect cube? (a) 100 (b) 69 (c) 64
  28. 28.What is the smallest whole number by which 49 must be multiplied to get a perfect cube?
  29. 29.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  30. 30.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  31. 31.What is 3³? =
  32. 32.What is 4³? =
  33. 33.What is 16³? =
  34. 34.What is ∛512? =
  35. 35.What is 18³? =
  36. 36.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  37. 37.What is ∛10648? =
  38. 38.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  39. 39.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  40. 40.What is ∛343? =

Answer key

  1. 125
  2. 6
  3. 7
  4. 2
  5. 2
  6. 27
  7. 25
  8. 4
  9. 27
  10. 2
  11. 1331
  12. 12
  13. 2197
  14. 25
  15. 1331
  16. 2
  17. 3
  18. 8000
  19. 9
  20. 15
  21. 5
  22. 125
  23. 17
  24. 729
  25. 3
  26. 9
  27. 64
  28. 7
  29. 19
  30. 27
  31. 27
  32. 64
  33. 4096
  34. 8
  35. 5832
  36. 8
  37. 22
  38. 7
  39. 11
  40. 7

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