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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 766 · 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 125 cubic cm. How long is each edge (in cm)?
  2. 2.What is 16³? =
  3. 3.What is ∛2197? =
  4. 4.What is ∛27? =
  5. 5.Which of these is a perfect cube? (a) 182 (b) 125 (c) 186
  6. 6.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  7. 7.What is ∛216? =
  8. 8.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  9. 9.Which of these is a perfect cube? (a) 2197 (b) 2278 (c) 2361
  10. 10.Which of these is a perfect cube? (a) 33 (b) 52 (c) 27
  11. 11.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  12. 12.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  13. 13.Which of these is a perfect cube? (a) 887 (b) 729 (c) 871
  14. 14.Which of these is a perfect cube? (a) 343 (b) 449 (c) 379
  15. 15.What is ∛2744? =
  16. 16.What is 13³? =
  17. 17.What is ∛3375? =
  18. 18.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  19. 19.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  20. 20.What is 8³? =
  21. 21.Which of these is a perfect cube? (a) 3392 (b) 3888 (c) 3375
  22. 22.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  23. 23.Which of these is a perfect cube? (a) 1364 (b) 1331 (c) 1608
  24. 24.Which of these is a perfect cube? (a) 1170 (b) 1000 (c) 1247
  25. 25.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  26. 26.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  27. 27.Which of these is a perfect cube? (a) 693 (b) 592 (c) 512
  28. 28.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  29. 29.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  30. 30.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  31. 31.What is 5³? =
  32. 32.What is the smallest whole number by which 135 must be multiplied to get a perfect cube?
  33. 33.What is ∛1000? =
  34. 34.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  35. 35.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  36. 36.What is 20³? =
  37. 37.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  38. 38.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  39. 39.What is 19³? =
  40. 40.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?

Answer key

  1. 5
  2. 4096
  3. 13
  4. 3
  5. 125
  6. 64
  7. 6
  8. 8
  9. 2197
  10. 27
  11. 216
  12. 9
  13. 729
  14. 343
  15. 14
  16. 2197
  17. 15
  18. 8
  19. 5
  20. 512
  21. 3375
  22. 25
  23. 1331
  24. 1000
  25. 64
  26. 2
  27. 512
  28. 27
  29. 2
  30. 2
  31. 125
  32. 25
  33. 10
  34. 9
  35. 8
  36. 8000
  37. 8
  38. 125
  39. 6859
  40. 64

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