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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 933 · 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 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  2. 2.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  3. 3.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  4. 4.What is ∛13824? =
  5. 5.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  6. 6.What is ∛2197? =
  7. 7.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  8. 8.What is ∛4913? =
  9. 9.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  10. 10.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  11. 11.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  12. 12.What is ∛125? =
  13. 13.What is ∛343? =
  14. 14.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  15. 15.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  16. 16.What is 10³? =
  17. 17.What is ∛2744? =
  18. 18.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  19. 19.What is 12³? =
  20. 20.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  21. 21.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  22. 22.Which of these is a perfect cube? (a) 3633 (b) 3384 (c) 3375
  23. 23.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  24. 24.What is 14³? =
  25. 25.What is ∛5832? =
  26. 26.What is the smallest whole number by which 3136 must be divided to get a perfect cube?
  27. 27.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  28. 28.What is ∛216? =
  29. 29.Which of these is a perfect cube? (a) 1394 (b) 1331 (c) 1366
  30. 30.Which of these is a perfect cube? (a) 961 (b) 899 (c) 729
  31. 31.Which of these is a perfect cube? (a) 27 (b) 31 (c) 52
  32. 32.Which of these is a perfect cube? (a) 227 (b) 237 (c) 216
  33. 33.Which of these is a perfect cube? (a) 2197 (b) 2562 (c) 2212
  34. 34.What is the smallest whole number by which 200 must be divided to get a perfect cube?
  35. 35.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  36. 36.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  37. 37.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  38. 38.What is ∛512? =
  39. 39.What is the smallest whole number by which 5 must be multiplied to get a perfect cube?
  40. 40.What is ∛1000? =

Answer key

  1. 216
  2. 20
  3. 125
  4. 24
  5. 13
  6. 13
  7. 27
  8. 17
  9. 6
  10. 9
  11. 17
  12. 5
  13. 7
  14. 125
  15. 2
  16. 1000
  17. 14
  18. 3
  19. 1728
  20. 12
  21. 7
  22. 3375
  23. 216
  24. 2744
  25. 18
  26. 49
  27. 8
  28. 6
  29. 1331
  30. 729
  31. 27
  32. 216
  33. 2197
  34. 25
  35. 25
  36. 19
  37. 15
  38. 8
  39. 25
  40. 10

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