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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 378 · 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 ∛3375? =
  2. 2.What is 18³? =
  3. 3.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  4. 4.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  5. 5.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  6. 6.What is 8³? =
  7. 7.What is 5³? =
  8. 8.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  9. 9.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  10. 10.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  11. 11.What is 4³? =
  12. 12.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  13. 13.Which of these is a perfect cube? (a) 101 (b) 83 (c) 64
  14. 14.What is ∛27? =
  15. 15.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  16. 16.What is ∛8000? =
  17. 17.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  18. 18.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  19. 19.What is ∛9261? =
  20. 20.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  21. 21.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  22. 22.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  23. 23.What is ∛12167? =
  24. 24.Which of these is a perfect cube? (a) 670 (b) 550 (c) 512
  25. 25.What is 12³? =
  26. 26.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  27. 27.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  28. 28.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  29. 29.What is the smallest whole number by which 10584 must be divided to get a perfect cube?
  30. 30.Which of these is a perfect cube? (a) 27 (b) 51 (c) 30
  31. 31.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  32. 32.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  33. 33.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  34. 34.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  35. 35.What is ∛15625? =
  36. 36.Which of these is a perfect cube? (a) 467 (b) 475 (c) 343
  37. 37.What is ∛6859? =
  38. 38.What is 16³? =
  39. 39.What is the smallest whole number by which 392 must be divided to get a perfect cube?
  40. 40.What is ∛1000? =

Answer key

  1. 15
  2. 5832
  3. 49
  4. 16
  5. 25
  6. 512
  7. 125
  8. 17
  9. 2
  10. 27
  11. 64
  12. 64
  13. 64
  14. 3
  15. 125
  16. 20
  17. 8
  18. 2
  19. 21
  20. 3
  21. 49
  22. 4
  23. 23
  24. 512
  25. 1728
  26. 27
  27. 5
  28. 8
  29. 49
  30. 27
  31. 5
  32. 9
  33. 12
  34. 3
  35. 25
  36. 343
  37. 19
  38. 4096
  39. 49
  40. 10

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