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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 877 · 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 4³? =
  2. 2.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  3. 3.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  4. 4.Which of these is a perfect cube? (a) 859 (b) 774 (c) 729
  5. 5.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  6. 6.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  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 ∛6859? =
  9. 9.Which of these is a perfect cube? (a) 1000 (b) 1051 (c) 1028
  10. 10.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  11. 11.Which of these is a perfect cube? (a) 91 (b) 86 (c) 64
  12. 12.What is 15³? =
  13. 13.What is ∛2197? =
  14. 14.What is 5³? =
  15. 15.What is ∛8? =
  16. 16.What is ∛512? =
  17. 17.What is ∛216? =
  18. 18.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  19. 19.What is the smallest whole number by which 72 must be multiplied to get a perfect cube?
  20. 20.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  21. 21.What is ∛343? =
  22. 22.What is ∛10648? =
  23. 23.Which of these is a perfect cube? (a) 2197 (b) 2624 (c) 2345
  24. 24.What is 6³? =
  25. 25.What is the smallest whole number by which 243 must be multiplied to get a perfect cube?
  26. 26.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  27. 27.What is 2³? =
  28. 28.What is ∛4096? =
  29. 29.What is the smallest whole number by which 448 must be divided to get a perfect cube?
  30. 30.What is 14³? =
  31. 31.Which of these is a perfect cube? (a) 125 (b) 174 (c) 133
  32. 32.Which of these is a perfect cube? (a) 1759 (b) 1926 (c) 1728
  33. 33.What is ∛729? =
  34. 34.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  35. 35.What is the smallest whole number by which 1944 must be divided to get a perfect cube?
  36. 36.Which of these is a perfect cube? (a) 45 (b) 28 (c) 27
  37. 37.What is 13³? =
  38. 38.What is 9³? =
  39. 39.What is the smallest whole number by which 3 must be divided to get a perfect cube?
  40. 40.What is the smallest whole number by which 3136 must be multiplied to get a perfect cube?

Answer key

  1. 64
  2. 27
  3. 2
  4. 729
  5. 2
  6. 216
  7. 64
  8. 19
  9. 1000
  10. 3
  11. 64
  12. 3375
  13. 13
  14. 125
  15. 2
  16. 8
  17. 6
  18. 7
  19. 3
  20. 14
  21. 7
  22. 22
  23. 2197
  24. 216
  25. 3
  26. 4
  27. 8
  28. 16
  29. 7
  30. 2744
  31. 125
  32. 1728
  33. 9
  34. 4
  35. 9
  36. 27
  37. 2197
  38. 729
  39. 3
  40. 7

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