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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 943 · 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 ∛13824? =
  2. 2.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  3. 3.What is 7³? =
  4. 4.Which of these is a perfect cube? (a) 431 (b) 357 (c) 343
  5. 5.What is ∛12167? =
  6. 6.Which of these is a perfect cube? (a) 2572 (b) 2197 (c) 2283
  7. 7.A big cube of edge 9 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  8. 8.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛216? =
  10. 10.What is the smallest whole number by which 135 must be multiplied to get a perfect cube?
  11. 11.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  12. 12.What is 3³? =
  13. 13.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  14. 14.What is 10³? =
  15. 15.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  16. 16.What is 20³? =
  17. 17.What is ∛2197? =
  18. 18.What is the smallest whole number by which 32 must be divided to get a perfect cube?
  19. 19.What is ∛512? =
  20. 20.What is 2³? =
  21. 21.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  22. 22.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  23. 23.What is 18³? =
  24. 24.What is the smallest whole number by which 1323 must be multiplied to get a perfect cube?
  25. 25.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  26. 26.Which of these is a perfect cube? (a) 2839 (b) 3111 (c) 2744
  27. 27.What is the smallest whole number by which 1080 must be divided to get a perfect cube?
  28. 28.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  29. 29.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  30. 30.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  31. 31.What is 11³? =
  32. 32.A cube has a volume of 729 cubic cm. How long is each edge (in cm)?
  33. 33.What is ∛6859? =
  34. 34.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  35. 35.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  36. 36.What is 17³? =
  37. 37.Which of these is a perfect cube? (a) 1331 (b) 1560 (c) 1362
  38. 38.What is ∛8000? =
  39. 39.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  40. 40.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?

Answer key

  1. 24
  2. 125
  3. 343
  4. 343
  5. 23
  6. 2197
  7. 27
  8. 14
  9. 6
  10. 25
  11. 3
  12. 27
  13. 8
  14. 1000
  15. 17
  16. 8000
  17. 13
  18. 4
  19. 8
  20. 8
  21. 8
  22. 12
  23. 5832
  24. 7
  25. 5
  26. 2744
  27. 5
  28. 125
  29. 9
  30. 5
  31. 1331
  32. 9
  33. 19
  34. 8
  35. 5
  36. 4913
  37. 1331
  38. 20
  39. 64
  40. 8

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