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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 841 · 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 ∛10648? =
  2. 2.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  3. 3.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  4. 4.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  5. 5.Which of these is a perfect cube? (a) 346 (b) 343 (c) 421
  6. 6.What is 18³? =
  7. 7.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  8. 8.What is ∛8000? =
  9. 9.What is the smallest whole number by which 200 must be divided to get a perfect cube?
  10. 10.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  11. 11.What is ∛15625? =
  12. 12.What is 20³? =
  13. 13.Which of these is a perfect cube? (a) 2309 (b) 2197 (c) 2472
  14. 14.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  15. 15.What is the smallest whole number by which 250 must be divided to get a perfect cube?
  16. 16.What is 14³? =
  17. 17.What is 3³? =
  18. 18.What is the smallest whole number by which 256 must be multiplied to get a perfect cube?
  19. 19.What is 7³? =
  20. 20.What is ∛3375? =
  21. 21.A cube has a volume of 8000 cubic cm. How long is each edge (in cm)?
  22. 22.What is 10³? =
  23. 23.What is 5³? =
  24. 24.Which of these is a perfect cube? (a) 3398 (b) 3375 (c) 3981
  25. 25.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  26. 26.What is ∛12167? =
  27. 27.Which of these is a perfect cube? (a) 29 (b) 51 (c) 27
  28. 28.What is ∛27? =
  29. 29.What is the smallest whole number by which 72 must be divided to get a perfect cube?
  30. 30.Which of these is a perfect cube? (a) 3320 (b) 2852 (c) 2744
  31. 31.What is 16³? =
  32. 32.What is ∛4096? =
  33. 33.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  34. 34.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  35. 35.What is ∛343? =
  36. 36.What is 9³? =
  37. 37.What is 11³? =
  38. 38.Which of these is a perfect cube? (a) 64 (b) 100 (c) 81
  39. 39.Which of these is a perfect cube? (a) 931 (b) 729 (c) 814
  40. 40.What is 8³? =

Answer key

  1. 22
  2. 27
  3. 7
  4. 3
  5. 343
  6. 5832
  7. 64
  8. 20
  9. 25
  10. 9
  11. 25
  12. 8000
  13. 2197
  14. 64
  15. 2
  16. 2744
  17. 27
  18. 2
  19. 343
  20. 15
  21. 20
  22. 1000
  23. 125
  24. 3375
  25. 49
  26. 23
  27. 27
  28. 3
  29. 9
  30. 2744
  31. 4096
  32. 16
  33. 64
  34. 10
  35. 7
  36. 729
  37. 1331
  38. 64
  39. 729
  40. 512

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