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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 829 · 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 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  2. 2.What is 16³? =
  3. 3.What is ∛4913? =
  4. 4.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
  5. 5.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  6. 6.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  7. 7.What is ∛216? =
  8. 8.What is ∛343? =
  9. 9.What is ∛4096? =
  10. 10.What is 14³? =
  11. 11.Which of these is a perfect cube? (a) 169 (b) 184 (c) 125
  12. 12.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  13. 13.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  14. 14.Which of these is a perfect cube? (a) 386 (b) 346 (c) 343
  15. 15.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  16. 16.What is ∛1728? =
  17. 17.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  18. 18.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  19. 19.What is 19³? =
  20. 20.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  21. 21.What is 9³? =
  22. 22.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  23. 23.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  24. 24.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
  25. 25.Which of these is a perfect cube? (a) 1617 (b) 1331 (c) 1400
  26. 26.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  27. 27.Which of these is a perfect cube? (a) 937 (b) 729 (c) 874
  28. 28.What is ∛13824? =
  29. 29.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  30. 30.What is 5³? =
  31. 31.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  32. 32.Which of these is a perfect cube? (a) 270 (b) 216 (c) 273
  33. 33.What is 11³? =
  34. 34.What is ∛12167? =
  35. 35.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  36. 36.What is 15³? =
  37. 37.What is 13³? =
  38. 38.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  39. 39.Which of these is a perfect cube? (a) 516 (b) 512 (c) 557
  40. 40.What is the smallest whole number by which 500 must be divided to get a perfect cube?

Answer key

  1. 8
  2. 4096
  3. 17
  4. 9
  5. 14
  6. 4
  7. 6
  8. 7
  9. 16
  10. 2744
  11. 125
  12. 12
  13. 64
  14. 343
  15. 125
  16. 12
  17. 4
  18. 27
  19. 6859
  20. 20
  21. 729
  22. 2
  23. 5
  24. 2
  25. 1331
  26. 2
  27. 729
  28. 24
  29. 9
  30. 125
  31. 18
  32. 216
  33. 1331
  34. 23
  35. 4
  36. 3375
  37. 2197
  38. 15
  39. 512
  40. 4

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