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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 857 · 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.Which of these is a perfect cube? (a) 2744 (b) 3074 (c) 3293
  2. 2.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  3. 3.Which of these is a perfect cube? (a) 183 (b) 196 (c) 125
  4. 4.What is 19³? =
  5. 5.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  6. 6.What is 16³? =
  7. 7.What is ∛2197? =
  8. 8.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
  9. 9.What is ∛64? =
  10. 10.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  11. 11.What is 6³? =
  12. 12.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  13. 13.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  14. 14.What is 3³? =
  15. 15.What is ∛125? =
  16. 16.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  17. 17.A big cube of edge 5 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  18. 18.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  19. 19.What is the smallest whole number by which 7 must be divided to get a perfect cube?
  20. 20.Which of these is a perfect cube? (a) 78 (b) 101 (c) 64
  21. 21.What is the smallest whole number by which 54 must be divided to get a perfect cube?
  22. 22.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  23. 23.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  24. 24.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  25. 25.What is the smallest whole number by which 875 must be multiplied to get a perfect cube?
  26. 26.What is the smallest whole number by which 81 must be divided to get a perfect cube?
  27. 27.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  28. 28.Which of these is a perfect cube? (a) 825 (b) 905 (c) 729
  29. 29.What is 5³? =
  30. 30.Which of these is a perfect cube? (a) 312 (b) 217 (c) 216
  31. 31.What is the smallest whole number by which 108 must be divided to get a perfect cube?
  32. 32.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  33. 33.What is ∛1000? =
  34. 34.Which of these is a perfect cube? (a) 1546 (b) 1331 (c) 1499
  35. 35.What is 7³? =
  36. 36.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  37. 37.Which of these is a perfect cube? (a) 512 (b) 591 (c) 699
  38. 38.What is 4³? =
  39. 39.What is the smallest whole number by which 189 must be multiplied to get a perfect cube?
  40. 40.Which of these is a perfect cube? (a) 1728 (b) 1836 (c) 1825

Answer key

  1. 2744
  2. 4
  3. 125
  4. 6859
  5. 9
  6. 4096
  7. 13
  8. 25
  9. 4
  10. 3
  11. 216
  12. 2
  13. 125
  14. 27
  15. 5
  16. 8
  17. 125
  18. 17
  19. 7
  20. 64
  21. 2
  22. 4
  23. 2
  24. 8
  25. 49
  26. 3
  27. 11
  28. 729
  29. 125
  30. 216
  31. 4
  32. 8
  33. 10
  34. 1331
  35. 343
  36. 15
  37. 512
  38. 64
  39. 49
  40. 1728

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