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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 310 · 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.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  2. 2.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  3. 3.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  4. 4.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  5. 5.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  6. 6.What is the smallest whole number by which 24 must be multiplied to get a perfect cube?
  7. 7.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  8. 8.Which of these is a perfect cube? (a) 1036 (b) 1000 (c) 1126
  9. 9.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  10. 10.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  11. 11.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  12. 12.What is 19³? =
  13. 13.What is ∛15625? =
  14. 14.What is the smallest whole number by which 392 must be multiplied to get a perfect cube?
  15. 15.What is ∛343? =
  16. 16.What is the smallest whole number by which 200 must be divided to get a perfect cube?
  17. 17.Which of these is a perfect cube? (a) 164 (b) 163 (c) 125
  18. 18.What is 5³? =
  19. 19.What is 2³? =
  20. 20.What is ∛27? =
  21. 21.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  22. 22.What is 6³? =
  23. 23.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  24. 24.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  25. 25.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  26. 26.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  27. 27.What is ∛1000? =
  28. 28.Which of these is a perfect cube? (a) 2833 (b) 2973 (c) 2744
  29. 29.What is the smallest whole number by which 432 must be divided to get a perfect cube?
  30. 30.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  31. 31.Which of these is a perfect cube? (a) 2360 (b) 2385 (c) 2197
  32. 32.What is 3³? =
  33. 33.What is 11³? =
  34. 34.What is ∛5832? =
  35. 35.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  36. 36.Which of these is a perfect cube? (a) 729 (b) 879 (c) 903
  37. 37.What is 17³? =
  38. 38.What is ∛3375? =
  39. 39.What is the smallest whole number by which 56 must be multiplied to get a perfect cube?
  40. 40.What is ∛2197? =

Answer key

  1. 3
  2. 125
  3. 12
  4. 5
  5. 13
  6. 9
  7. 5
  8. 1000
  9. 9
  10. 64
  11. 9
  12. 6859
  13. 25
  14. 7
  15. 7
  16. 25
  17. 125
  18. 125
  19. 8
  20. 3
  21. 6
  22. 216
  23. 18
  24. 125
  25. 5
  26. 14
  27. 10
  28. 2744
  29. 2
  30. 4
  31. 2197
  32. 27
  33. 1331
  34. 18
  35. 8
  36. 729
  37. 4913
  38. 15
  39. 49
  40. 13

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