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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 77 · 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 big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  2. 2.Which of these is a perfect cube? (a) 2914 (b) 3199 (c) 2744
  3. 3.What is 9³? =
  4. 4.What is 16³? =
  5. 5.Which of these is a perfect cube? (a) 1055 (b) 1000 (c) 1202
  6. 6.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  7. 7.Which of these is a perfect cube? (a) 3558 (b) 3829 (c) 3375
  8. 8.What is ∛10648? =
  9. 9.What is ∛2744? =
  10. 10.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  11. 11.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  12. 12.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  13. 13.What is 14³? =
  14. 14.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  15. 15.What is ∛216? =
  16. 16.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  17. 17.What is 12³? =
  18. 18.What is 2³? =
  19. 19.What is ∛8000? =
  20. 20.What is ∛9261? =
  21. 21.Which of these is a perfect cube? (a) 1331 (b) 1467 (c) 1637
  22. 22.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  23. 23.What is 6³? =
  24. 24.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  25. 25.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  26. 26.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  27. 27.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  28. 28.What is 13³? =
  29. 29.What is 19³? =
  30. 30.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  31. 31.What is the smallest whole number by which 3125 must be multiplied to get a perfect cube?
  32. 32.What is ∛512? =
  33. 33.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  34. 34.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  35. 35.What is 7³? =
  36. 36.Which of these is a perfect cube? (a) 75 (b) 64 (c) 67
  37. 37.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  38. 38.What is ∛8? =
  39. 39.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  40. 40.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?

Answer key

  1. 8
  2. 2744
  3. 729
  4. 4096
  5. 1000
  6. 7
  7. 3375
  8. 22
  9. 14
  10. 8
  11. 49
  12. 25
  13. 2744
  14. 9
  15. 6
  16. 3
  17. 1728
  18. 8
  19. 20
  20. 21
  21. 1331
  22. 3
  23. 216
  24. 11
  25. 16
  26. 4
  27. 5
  28. 2197
  29. 6859
  30. 216
  31. 5
  32. 8
  33. 15
  34. 64
  35. 343
  36. 64
  37. 216
  38. 2
  39. 7
  40. 8

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