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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 674 · 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 243 must be divided to get a perfect cube?
  2. 2.What is ∛125? =
  3. 3.What is the smallest whole number by which 648 must be divided to get a perfect cube?
  4. 4.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  5. 5.What is ∛512? =
  6. 6.What is 5³? =
  7. 7.Which of these is a perfect cube? (a) 2318 (b) 2325 (c) 2197
  8. 8.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  9. 9.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  10. 10.What is ∛4913? =
  11. 11.Which of these is a perfect cube? (a) 170 (b) 125 (c) 181
  12. 12.Which of these is a perfect cube? (a) 3375 (b) 3526 (c) 3759
  13. 13.What is ∛10648? =
  14. 14.What is 19³? =
  15. 15.Which of these is a perfect cube? (a) 246 (b) 216 (c) 297
  16. 16.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  17. 17.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  18. 18.What is ∛216? =
  19. 19.What is 15³? =
  20. 20.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  21. 21.Which of these is a perfect cube? (a) 1448 (b) 1485 (c) 1331
  22. 22.What is the smallest whole number by which 1512 must be multiplied to get a perfect cube?
  23. 23.What is ∛1331? =
  24. 24.What is ∛27? =
  25. 25.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  26. 26.What is ∛5832? =
  27. 27.What is 10³? =
  28. 28.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  29. 29.What is 11³? =
  30. 30.What is ∛15625? =
  31. 31.What is the smallest whole number by which 6125 must be multiplied to get a perfect cube?
  32. 32.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  33. 33.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  34. 34.What is the smallest whole number by which 9 must be divided to get a perfect cube?
  35. 35.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  36. 36.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  37. 37.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  38. 38.What is 17³? =
  39. 39.Which of these is a perfect cube? (a) 27 (b) 38 (c) 40
  40. 40.What is the smallest whole number by which 432 must be divided to get a perfect cube?

Answer key

  1. 9
  2. 5
  3. 3
  4. 125
  5. 8
  6. 125
  7. 2197
  8. 13
  9. 64
  10. 17
  11. 125
  12. 3375
  13. 22
  14. 6859
  15. 216
  16. 216
  17. 19
  18. 6
  19. 3375
  20. 2
  21. 1331
  22. 49
  23. 11
  24. 3
  25. 9
  26. 18
  27. 1000
  28. 64
  29. 1331
  30. 25
  31. 7
  32. 6
  33. 3
  34. 9
  35. 216
  36. 9
  37. 8
  38. 4913
  39. 27
  40. 2

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