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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 512 · 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 ∛2744? =
  2. 2.What is 19³? =
  3. 3.Which of these is a perfect cube? (a) 1290 (b) 1273 (c) 1000
  4. 4.What is ∛64? =
  5. 5.What is ∛343? =
  6. 6.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  7. 7.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  8. 8.Which of these is a perfect cube? (a) 125 (b) 159 (c) 126
  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 ∛1000? =
  11. 11.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  12. 12.What is ∛12167? =
  13. 13.What is 4³? =
  14. 14.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  15. 15.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  16. 16.What is ∛5832? =
  17. 17.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  18. 18.What is 18³? =
  19. 19.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  20. 20.What is 3³? =
  21. 21.What is ∛125? =
  22. 22.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  23. 23.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  24. 24.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  25. 25.Which of these is a perfect cube? (a) 2391 (b) 2197 (c) 2365
  26. 26.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  27. 27.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  28. 28.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  29. 29.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  30. 30.Which of these is a perfect cube? (a) 2095 (b) 1762 (c) 1728
  31. 31.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  32. 32.What is ∛729? =
  33. 33.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  34. 34.What is 15³? =
  35. 35.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  36. 36.What is the smallest whole number by which 189 must be divided to get a perfect cube?
  37. 37.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  38. 38.What is 2³? =
  39. 39.What is ∛512? =
  40. 40.What is 5³? =

Answer key

  1. 14
  2. 6859
  3. 1000
  4. 4
  5. 7
  6. 4
  7. 5
  8. 125
  9. 64
  10. 10
  11. 125
  12. 23
  13. 64
  14. 125
  15. 9
  16. 18
  17. 2
  18. 5832
  19. 8
  20. 27
  21. 5
  22. 5
  23. 12
  24. 3
  25. 2197
  26. 8
  27. 64
  28. 9
  29. 125
  30. 1728
  31. 3
  32. 9
  33. 7
  34. 3375
  35. 8
  36. 7
  37. 2
  38. 8
  39. 8
  40. 125

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