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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 238 · 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 19³? =
  2. 2.What is 3³? =
  3. 3.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  4. 4.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  5. 5.What is the smallest whole number by which 10584 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 17³? =
  8. 8.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  9. 9.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  10. 10.What is 14³? =
  11. 11.What is 20³? =
  12. 12.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  13. 13.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  14. 14.What is 4³? =
  15. 15.What is 2³? =
  16. 16.What is 8³? =
  17. 17.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  18. 18.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  19. 19.What is 18³? =
  20. 20.Which of these is a perfect cube? (a) 64 (b) 105 (c) 91
  21. 21.What is ∛343? =
  22. 22.What is 7³? =
  23. 23.What is 12³? =
  24. 24.Which of these is a perfect cube? (a) 343 (b) 386 (c) 357
  25. 25.Which of these is a perfect cube? (a) 804 (b) 729 (c) 874
  26. 26.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  27. 27.Which of these is a perfect cube? (a) 1331 (b) 1648 (c) 1504
  28. 28.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  29. 29.What is ∛8? =
  30. 30.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  31. 31.What is the smallest whole number by which 3125 must be divided to get a perfect cube?
  32. 32.Which of these is a perfect cube? (a) 1000 (b) 1171 (c) 1219
  33. 33.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  34. 34.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  35. 35.Which of these is a perfect cube? (a) 27 (b) 50 (c) 34
  36. 36.What is ∛729? =
  37. 37.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  38. 38.Which of these is a perfect cube? (a) 3388 (b) 3588 (c) 3375
  39. 39.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
  40. 40.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?

Answer key

  1. 6859
  2. 27
  3. 49
  4. 12
  5. 49
  6. 2
  7. 4913
  8. 3
  9. 2
  10. 2744
  11. 8000
  12. 216
  13. 4
  14. 64
  15. 8
  16. 512
  17. 13
  18. 5
  19. 5832
  20. 64
  21. 7
  22. 343
  23. 1728
  24. 343
  25. 729
  26. 9
  27. 1331
  28. 5
  29. 2
  30. 7
  31. 25
  32. 1000
  33. 9
  34. 64
  35. 27
  36. 9
  37. 7
  38. 3375
  39. 2
  40. 9

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