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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 735 · 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.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  2. 2.What is the smallest whole number by which 6125 must be divided to get a perfect cube?
  3. 3.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  4. 4.What is 15³? =
  5. 5.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  7. 7.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  8. 8.What is ∛13824? =
  9. 9.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  10. 10.What is 17³? =
  11. 11.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  12. 12.Which of these is a perfect cube? (a) 1281 (b) 1000 (c) 1013
  13. 13.What is 4³? =
  14. 14.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  15. 15.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  16. 16.Which of these is a perfect cube? (a) 1459 (b) 1444 (c) 1331
  17. 17.Which of these is a perfect cube? (a) 216 (b) 277 (c) 256
  18. 18.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  19. 19.What is the smallest whole number by which 7 must be divided to get a perfect cube?
  20. 20.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  21. 21.What is 2³? =
  22. 22.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  23. 23.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  24. 24.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  25. 25.What is ∛216? =
  26. 26.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  27. 27.What is ∛4913? =
  28. 28.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  29. 29.What is the smallest whole number by which 675 must be divided to get a perfect cube?
  30. 30.What is the smallest whole number by which 500 must be divided to get a perfect cube?
  31. 31.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  32. 32.Which of these is a perfect cube? (a) 3375 (b) 3908 (c) 3898
  33. 33.What is 6³? =
  34. 34.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  35. 35.What is ∛343? =
  36. 36.What is 16³? =
  37. 37.Which of these is a perfect cube? (a) 90 (b) 64 (c) 79
  38. 38.Which of these is a perfect cube? (a) 779 (b) 788 (c) 729
  39. 39.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  40. 40.Which of these is a perfect cube? (a) 2958 (b) 2744 (c) 3065

Answer key

  1. 20
  2. 49
  3. 19
  4. 3375
  5. 216
  6. 5
  7. 27
  8. 24
  9. 49
  10. 4913
  11. 8
  12. 1000
  13. 64
  14. 3
  15. 64
  16. 1331
  17. 216
  18. 25
  19. 7
  20. 9
  21. 8
  22. 64
  23. 25
  24. 15
  25. 6
  26. 10
  27. 17
  28. 5
  29. 25
  30. 4
  31. 5
  32. 3375
  33. 216
  34. 7
  35. 7
  36. 4096
  37. 64
  38. 729
  39. 125
  40. 2744

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