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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 552 · 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 ∛1331? =
  2. 2.What is 3³? =
  3. 3.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  4. 4.What is 16³? =
  5. 5.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  6. 6.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  7. 7.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  8. 8.Which of these is a perfect cube? (a) 1331 (b) 1612 (c) 1386
  9. 9.Which of these is a perfect cube? (a) 2197 (b) 2617 (c) 2534
  10. 10.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  11. 11.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  12. 12.What is 4³? =
  13. 13.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  14. 14.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  15. 15.What is ∛4913? =
  16. 16.What is ∛13824? =
  17. 17.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  18. 18.What is 18³? =
  19. 19.What is 13³? =
  20. 20.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  21. 21.What is 9³? =
  22. 22.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  23. 23.What is ∛2744? =
  24. 24.Which of these is a perfect cube? (a) 3443 (b) 3375 (c) 3640
  25. 25.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  26. 26.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  27. 27.What is ∛729? =
  28. 28.What is 7³? =
  29. 29.Which of these is a perfect cube? (a) 746 (b) 729 (c) 919
  30. 30.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  31. 31.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  32. 32.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  33. 33.What is 17³? =
  34. 34.What is 14³? =
  35. 35.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  36. 36.What is 6³? =
  37. 37.Which of these is a perfect cube? (a) 88 (b) 64 (c) 109
  38. 38.What is the smallest whole number by which 3136 must be divided to get a perfect cube?
  39. 39.Which of these is a perfect cube? (a) 125 (b) 162 (c) 139
  40. 40.What is ∛3375? =

Answer key

  1. 11
  2. 27
  3. 25
  4. 4096
  5. 9
  6. 2
  7. 49
  8. 1331
  9. 2197
  10. 8
  11. 7
  12. 64
  13. 2
  14. 19
  15. 17
  16. 24
  17. 8
  18. 5832
  19. 2197
  20. 5
  21. 729
  22. 125
  23. 14
  24. 3375
  25. 2
  26. 8
  27. 9
  28. 343
  29. 729
  30. 49
  31. 2
  32. 13
  33. 4913
  34. 2744
  35. 3
  36. 216
  37. 64
  38. 49
  39. 125
  40. 15

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