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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 209 · 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 big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  2. 2.What is 7³? =
  3. 3.What is 6³? =
  4. 4.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  5. 5.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  6. 6.What is the smallest whole number by which 1125 must be multiplied to get a perfect cube?
  7. 7.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  8. 8.Which of these is a perfect cube? (a) 27 (b) 48 (c) 34
  9. 9.Which of these is a perfect cube? (a) 1104 (b) 1158 (c) 1000
  10. 10.Which of these is a perfect cube? (a) 560 (b) 536 (c) 512
  11. 11.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  12. 12.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  13. 13.Which of these is a perfect cube? (a) 2406 (b) 2308 (c) 2197
  14. 14.What is 19³? =
  15. 15.What is the smallest whole number by which 1080 must be divided to get a perfect cube?
  16. 16.What is ∛4096? =
  17. 17.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  18. 18.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  19. 19.Which of these is a perfect cube? (a) 1484 (b) 1516 (c) 1331
  20. 20.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  21. 21.What is 4³? =
  22. 22.What is ∛6859? =
  23. 23.What is 9³? =
  24. 24.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  25. 25.What is 15³? =
  26. 26.What is the smallest whole number by which 16 must be divided to get a perfect cube?
  27. 27.What is ∛2197? =
  28. 28.Which of these is a perfect cube? (a) 2744 (b) 3268 (c) 3011
  29. 29.Which of these is a perfect cube? (a) 1828 (b) 2143 (c) 1728
  30. 30.What is 20³? =
  31. 31.What is ∛512? =
  32. 32.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  33. 33.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
  34. 34.What is ∛216? =
  35. 35.What is the smallest whole number by which 375 must be multiplied to get a perfect cube?
  36. 36.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  37. 37.What is 10³? =
  38. 38.What is 18³? =
  39. 39.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  40. 40.Which of these is a perfect cube? (a) 776 (b) 729 (c) 875

Answer key

  1. 125
  2. 343
  3. 216
  4. 17
  5. 216
  6. 3
  7. 5
  8. 27
  9. 1000
  10. 512
  11. 8
  12. 216
  13. 2197
  14. 6859
  15. 5
  16. 16
  17. 3
  18. 4
  19. 1331
  20. 7
  21. 64
  22. 19
  23. 729
  24. 8
  25. 3375
  26. 2
  27. 13
  28. 2744
  29. 1728
  30. 8000
  31. 8
  32. 12
  33. 49
  34. 6
  35. 9
  36. 6
  37. 1000
  38. 5832
  39. 8
  40. 729

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