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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 4 · 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 320 must be divided to get a perfect cube?
  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.What is 7³? =
  4. 4.Which of these is a perfect cube? (a) 2234 (b) 2661 (c) 2197
  5. 5.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  6. 6.What is ∛8000? =
  7. 7.Which of these is a perfect cube? (a) 1292 (b) 1000 (c) 1118
  8. 8.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  9. 9.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  10. 10.Which of these is a perfect cube? (a) 645 (b) 544 (c) 512
  11. 11.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  12. 12.Which of these is a perfect cube? (a) 1728 (b) 1864 (c) 2121
  13. 13.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  14. 14.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  15. 15.Which of these is a perfect cube? (a) 48 (b) 53 (c) 27
  16. 16.What is ∛4096? =
  17. 17.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  18. 18.What is ∛10648? =
  19. 19.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
  20. 20.What is the smallest whole number by which 189 must be divided to get a perfect cube?
  21. 21.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  22. 22.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  23. 23.What is the smallest whole number by which 4 must be divided to get a perfect cube?
  24. 24.Which of these is a perfect cube? (a) 2744 (b) 3017 (c) 3136
  25. 25.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  26. 26.What is ∛4913? =
  27. 27.What is the smallest whole number by which 1323 must be divided to get a perfect cube?
  28. 28.What is 19³? =
  29. 29.What is the smallest whole number by which 192 must be multiplied to get a perfect cube?
  30. 30.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  31. 31.What is 20³? =
  32. 32.What is 6³? =
  33. 33.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
  34. 34.Which of these is a perfect cube? (a) 216 (b) 304 (c) 234
  35. 35.What is 8³? =
  36. 36.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  37. 37.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  38. 38.What is ∛1000? =
  39. 39.What is ∛8? =
  40. 40.What is 12³? =

Answer key

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

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