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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 654 · 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 the smallest whole number by which 675 must be divided to get a perfect cube?
  2. 2.What is ∛5832? =
  3. 3.What is 4³? =
  4. 4.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  5. 5.What is ∛6859? =
  6. 6.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  7. 7.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  8. 8.What is ∛8000? =
  9. 9.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  10. 10.What is ∛216? =
  11. 11.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  12. 12.What is 11³? =
  13. 13.Which of these is a perfect cube? (a) 450 (b) 343 (c) 458
  14. 14.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  15. 15.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  16. 16.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  17. 17.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  18. 18.What is 18³? =
  19. 19.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  20. 20.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  21. 21.What is the smallest whole number by which 648 must be multiplied to get a perfect cube?
  22. 22.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  23. 23.What is 15³? =
  24. 24.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  25. 25.Which of these is a perfect cube? (a) 1381 (b) 1547 (c) 1331
  26. 26.What is the smallest whole number by which 500 must be divided to get a perfect cube?
  27. 27.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  28. 28.What is 20³? =
  29. 29.What is the smallest whole number by which 108 must be divided to get a perfect cube?
  30. 30.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  31. 31.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  32. 32.What is 19³? =
  33. 33.Which of these is a perfect cube? (a) 78 (b) 67 (c) 64
  34. 34.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  35. 35.What is 2³? =
  36. 36.What is ∛15625? =
  37. 37.What is ∛9261? =
  38. 38.What is the smallest whole number by which 875 must be divided to get a perfect cube?
  39. 39.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  40. 40.What is the smallest whole number by which 25 must be divided to get a perfect cube?

Answer key

  1. 25
  2. 18
  3. 64
  4. 64
  5. 19
  6. 9
  7. 9
  8. 20
  9. 64
  10. 6
  11. 4
  12. 1331
  13. 343
  14. 125
  15. 64
  16. 9
  17. 27
  18. 5832
  19. 27
  20. 4
  21. 9
  22. 12
  23. 3375
  24. 15
  25. 1331
  26. 4
  27. 2
  28. 8000
  29. 4
  30. 14
  31. 10
  32. 6859
  33. 64
  34. 8
  35. 8
  36. 25
  37. 21
  38. 7
  39. 3
  40. 25

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