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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 669 · 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 11³? =
  2. 2.What is 5³? =
  3. 3.What is 14³? =
  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 the smallest whole number by which 1125 must be divided to get a perfect cube?
  6. 6.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  7. 7.Which of these is a perfect cube? (a) 125 (b) 131 (c) 178
  8. 8.Which of these is a perfect cube? (a) 216 (b) 293 (c) 270
  9. 9.Which of these is a perfect cube? (a) 2520 (b) 2436 (c) 2197
  10. 10.What is 16³? =
  11. 11.What is ∛13824? =
  12. 12.What is 9³? =
  13. 13.What is ∛10648? =
  14. 14.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  15. 15.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  16. 16.What is ∛8? =
  17. 17.Which of these is a perfect cube? (a) 54 (b) 27 (c) 46
  18. 18.Which of these is a perfect cube? (a) 831 (b) 946 (c) 729
  19. 19.What is ∛15625? =
  20. 20.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  21. 21.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  22. 22.What is 17³? =
  23. 23.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  24. 24.Which of these is a perfect cube? (a) 1000 (b) 1016 (c) 1056
  25. 25.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  26. 26.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  27. 27.What is ∛343? =
  28. 28.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  29. 29.What is 20³? =
  30. 30.What is the smallest whole number by which 24 must be divided to get a perfect cube?
  31. 31.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  32. 32.What is 3³? =
  33. 33.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  34. 34.What is 4³? =
  35. 35.Which of these is a perfect cube? (a) 1618 (b) 1607 (c) 1331
  36. 36.What is 19³? =
  37. 37.What is the smallest whole number by which 500 must be multiplied to get a perfect cube?
  38. 38.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  39. 39.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  40. 40.What is ∛216? =

Answer key

  1. 1331
  2. 125
  3. 2744
  4. 125
  5. 9
  6. 27
  7. 125
  8. 216
  9. 2197
  10. 4096
  11. 24
  12. 729
  13. 22
  14. 3
  15. 8
  16. 2
  17. 27
  18. 729
  19. 25
  20. 9
  21. 4
  22. 4913
  23. 18
  24. 1000
  25. 4
  26. 3
  27. 7
  28. 7
  29. 8000
  30. 3
  31. 8
  32. 27
  33. 13
  34. 64
  35. 1331
  36. 6859
  37. 2
  38. 125
  39. 2
  40. 6

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