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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 156 · 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 392 must be multiplied to get a perfect cube?
  2. 2.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  3. 3.What is ∛1331? =
  4. 4.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?
  5. 5.Which of these is a perfect cube? (a) 2012 (b) 1728 (c) 2157
  6. 6.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  7. 7.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  8. 8.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛1000? =
  10. 10.What is 8³? =
  11. 11.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  12. 12.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  13. 13.Which of these is a perfect cube? (a) 64 (b) 90 (c) 80
  14. 14.What is 3³? =
  15. 15.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  16. 16.What is ∛216? =
  17. 17.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  18. 18.What is ∛125? =
  19. 19.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  20. 20.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  21. 21.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  22. 22.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  23. 23.Which of these is a perfect cube? (a) 1114 (b) 1000 (c) 1288
  24. 24.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  25. 25.What is 19³? =
  26. 26.Which of these is a perfect cube? (a) 786 (b) 840 (c) 729
  27. 27.What is 7³? =
  28. 28.What is 20³? =
  29. 29.What is 5³? =
  30. 30.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  31. 31.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  32. 32.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  33. 33.What is 12³? =
  34. 34.What is ∛512? =
  35. 35.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  36. 36.What is ∛12167? =
  37. 37.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  38. 38.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  39. 39.What is ∛27? =
  40. 40.What is ∛10648? =

Answer key

  1. 7
  2. 2
  3. 11
  4. 7
  5. 1728
  6. 8
  7. 8
  8. 17
  9. 10
  10. 512
  11. 20
  12. 8
  13. 64
  14. 27
  15. 16
  16. 6
  17. 3
  18. 5
  19. 3
  20. 19
  21. 64
  22. 2
  23. 1000
  24. 11
  25. 6859
  26. 729
  27. 343
  28. 8000
  29. 125
  30. 7
  31. 15
  32. 4
  33. 1728
  34. 8
  35. 5
  36. 23
  37. 3
  38. 4
  39. 3
  40. 22

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