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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 201 · 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 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  2. 2.What is 7³? =
  3. 3.What is ∛4096? =
  4. 4.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  5. 5.Which of these is a perfect cube? (a) 512 (b) 688 (c) 566
  6. 6.Which of these is a perfect cube? (a) 76 (b) 70 (c) 64
  7. 7.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  8. 8.What is 12³? =
  9. 9.What is 10³? =
  10. 10.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  11. 11.Which of these is a perfect cube? (a) 2636 (b) 2380 (c) 2197
  12. 12.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  13. 13.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  14. 14.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  15. 15.What is ∛1331? =
  16. 16.What is ∛125? =
  17. 17.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  18. 18.What is 4³? =
  19. 19.What is ∛216? =
  20. 20.Which of these is a perfect cube? (a) 27 (b) 28 (c) 31
  21. 21.What is ∛343? =
  22. 22.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  23. 23.What is the smallest whole number by which 25 must be divided to get a perfect cube?
  24. 24.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  25. 25.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
  26. 26.What is 19³? =
  27. 27.What is ∛512? =
  28. 28.Which of these is a perfect cube? (a) 216 (b) 241 (c) 314
  29. 29.What is ∛3375? =
  30. 30.What is 15³? =
  31. 31.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  32. 32.What is 16³? =
  33. 33.What is the smallest whole number by which 24 must be divided to get a perfect cube?
  34. 34.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  35. 35.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  36. 36.What is 2³? =
  37. 37.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  38. 38.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  39. 39.Which of these is a perfect cube? (a) 151 (b) 127 (c) 125
  40. 40.What is 14³? =

Answer key

  1. 27
  2. 343
  3. 16
  4. 125
  5. 512
  6. 64
  7. 8
  8. 1728
  9. 1000
  10. 7
  11. 2197
  12. 216
  13. 27
  14. 64
  15. 11
  16. 5
  17. 27
  18. 64
  19. 6
  20. 27
  21. 7
  22. 14
  23. 25
  24. 9
  25. 3
  26. 6859
  27. 8
  28. 216
  29. 15
  30. 3375
  31. 4
  32. 4096
  33. 3
  34. 8
  35. 49
  36. 8
  37. 17
  38. 3
  39. 125
  40. 2744

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