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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 510 · 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 ∛343? =
  2. 2.Which of these is a perfect cube? (a) 2041 (b) 1872 (c) 1728
  3. 3.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  4. 4.What is 10³? =
  5. 5.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  6. 6.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  7. 7.Which of these is a perfect cube? (a) 1000 (b) 1027 (c) 1186
  8. 8.What is 9³? =
  9. 9.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  10. 10.What is ∛8000? =
  11. 11.What is 12³? =
  12. 12.What is 17³? =
  13. 13.Which of these is a perfect cube? (a) 2197 (b) 2355 (c) 2216
  14. 14.What is ∛216? =
  15. 15.What is ∛729? =
  16. 16.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  17. 17.What is the smallest whole number by which 625 must be divided to get a perfect cube?
  18. 18.What is 8³? =
  19. 19.What is 14³? =
  20. 20.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
  21. 21.Which of these is a perfect cube? (a) 141 (b) 136 (c) 125
  22. 22.Which of these is a perfect cube? (a) 1331 (b) 1358 (c) 1535
  23. 23.What is the smallest whole number by which 500 must be divided to get a perfect cube?
  24. 24.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  25. 25.What is ∛64? =
  26. 26.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  27. 27.Which of these is a perfect cube? (a) 106 (b) 96 (c) 64
  28. 28.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  29. 29.What is ∛2744? =
  30. 30.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  31. 31.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  32. 32.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  33. 33.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  34. 34.What is 11³? =
  35. 35.What is ∛5832? =
  36. 36.What is 19³? =
  37. 37.What is ∛4096? =
  38. 38.What is 16³? =
  39. 39.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  40. 40.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?

Answer key

  1. 7
  2. 1728
  3. 20
  4. 1000
  5. 125
  6. 27
  7. 1000
  8. 729
  9. 216
  10. 20
  11. 1728
  12. 4913
  13. 2197
  14. 6
  15. 9
  16. 27
  17. 5
  18. 512
  19. 2744
  20. 3
  21. 125
  22. 1331
  23. 4
  24. 216
  25. 4
  26. 25
  27. 64
  28. 2
  29. 14
  30. 3
  31. 8
  32. 12
  33. 8
  34. 1331
  35. 18
  36. 6859
  37. 16
  38. 4096
  39. 2
  40. 9

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