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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 777 · 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 49 must be divided to get a perfect cube?
  2. 2.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  3. 3.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  4. 4.What is the smallest whole number by which 10584 must be multiplied to get a perfect cube?
  5. 5.What is 4³? =
  6. 6.What is ∛64? =
  7. 7.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  8. 8.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  9. 9.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  10. 10.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  11. 11.What is ∛3375? =
  12. 12.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  13. 13.Which of these is a perfect cube? (a) 152 (b) 127 (c) 125
  14. 14.What is the smallest whole number by which 625 must be multiplied to get a perfect cube?
  15. 15.Which of these is a perfect cube? (a) 44 (b) 36 (c) 27
  16. 16.Which of these is a perfect cube? (a) 647 (b) 568 (c) 512
  17. 17.What is 8³? =
  18. 18.What is 13³? =
  19. 19.What is ∛9261? =
  20. 20.What is ∛6859? =
  21. 21.What is ∛4096? =
  22. 22.What is ∛1000? =
  23. 23.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  24. 24.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  25. 25.What is the smallest whole number by which 72 must be divided to get a perfect cube?
  26. 26.What is 15³? =
  27. 27.What is ∛8? =
  28. 28.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
  29. 29.Which of these is a perfect cube? (a) 1186 (b) 1000 (c) 1066
  30. 30.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  31. 31.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  32. 32.Which of these is a perfect cube? (a) 86 (b) 83 (c) 64
  33. 33.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  34. 34.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  35. 35.What is the smallest whole number by which 32 must be multiplied to get a perfect cube?
  36. 36.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  37. 37.What is ∛13824? =
  38. 38.What is ∛512? =
  39. 39.Which of these is a perfect cube? (a) 729 (b) 758 (c) 857
  40. 40.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?

Answer key

  1. 49
  2. 6
  3. 216
  4. 7
  5. 64
  6. 4
  7. 27
  8. 15
  9. 3
  10. 64
  11. 15
  12. 64
  13. 125
  14. 25
  15. 27
  16. 512
  17. 512
  18. 2197
  19. 21
  20. 19
  21. 16
  22. 10
  23. 10
  24. 5
  25. 9
  26. 3375
  27. 2
  28. 3
  29. 1000
  30. 4
  31. 8
  32. 64
  33. 64
  34. 16
  35. 2
  36. 9
  37. 24
  38. 8
  39. 729
  40. 14

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