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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 684 · 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 ∛4096? =
  2. 2.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  3. 3.What is 17³? =
  4. 4.What is ∛1000? =
  5. 5.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  6. 6.What is 2³? =
  7. 7.What is the smallest whole number by which 81 must be divided to get a perfect cube?
  8. 8.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  9. 9.What is 13³? =
  10. 10.Which of these is a perfect cube? (a) 133 (b) 125 (c) 153
  11. 11.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  12. 12.What is 14³? =
  13. 13.Which of these is a perfect cube? (a) 316 (b) 216 (c) 293
  14. 14.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  15. 15.Which of these is a perfect cube? (a) 1683 (b) 1494 (c) 1331
  16. 16.What is ∛125? =
  17. 17.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  18. 18.What is ∛13824? =
  19. 19.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
  20. 20.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  21. 21.What is ∛10648? =
  22. 22.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  23. 23.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  24. 24.What is ∛343? =
  25. 25.What is 12³? =
  26. 26.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  27. 27.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  28. 28.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  29. 29.What is 16³? =
  30. 30.What is 15³? =
  31. 31.What is ∛15625? =
  32. 32.What is the smallest whole number by which 128 must be multiplied to get a perfect cube?
  33. 33.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  34. 34.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  35. 35.Which of these is a perfect cube? (a) 2534 (b) 2440 (c) 2197
  36. 36.What is the smallest whole number by which 320 must be multiplied to get a perfect cube?
  37. 37.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  38. 38.Which of these is a perfect cube? (a) 1217 (b) 1000 (c) 1203
  39. 39.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  40. 40.What is 18³? =

Answer key

  1. 16
  2. 4
  3. 4913
  4. 10
  5. 8
  6. 8
  7. 3
  8. 5
  9. 2197
  10. 125
  11. 14
  12. 2744
  13. 216
  14. 64
  15. 1331
  16. 5
  17. 125
  18. 24
  19. 49
  20. 9
  21. 22
  22. 3
  23. 5
  24. 7
  25. 1728
  26. 125
  27. 27
  28. 4
  29. 4096
  30. 3375
  31. 25
  32. 4
  33. 125
  34. 216
  35. 2197
  36. 25
  37. 6
  38. 1000
  39. 2
  40. 5832

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