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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 513 · 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 3136 must be multiplied to get a perfect cube?
  2. 2.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  3. 3.What is ∛2197? =
  4. 4.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  5. 5.What is the smallest whole number by which 576 must be divided to get a perfect cube?
  6. 6.A big cube of edge 2 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  7. 7.What is the smallest whole number by which 40 must be divided to get a perfect cube?
  8. 8.What is ∛64? =
  9. 9.What is 19³? =
  10. 10.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
  11. 11.A cube has a volume of 4913 cubic cm. How long is each edge (in cm)?
  12. 12.What is the smallest whole number by which 108 must be divided to get a perfect cube?
  13. 13.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  14. 14.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  15. 15.What is ∛1331? =
  16. 16.Which of these is a perfect cube? (a) 299 (b) 291 (c) 216
  17. 17.What is 8³? =
  18. 18.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  19. 19.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  20. 20.What is ∛5832? =
  21. 21.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  22. 22.Which of these is a perfect cube? (a) 1121 (b) 1000 (c) 1007
  23. 23.What is the smallest whole number by which 5400 must be multiplied to get a perfect cube?
  24. 24.What is ∛512? =
  25. 25.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  26. 26.What is 3³? =
  27. 27.Which of these is a perfect cube? (a) 431 (b) 343 (c) 436
  28. 28.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  29. 29.What is 7³? =
  30. 30.What is 17³? =
  31. 31.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  32. 32.What is the smallest whole number by which 72 must be divided to get a perfect cube?
  33. 33.What is ∛10648? =
  34. 34.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  35. 35.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  36. 36.What is 5³? =
  37. 37.A big cube of edge 6 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  38. 38.What is ∛9261? =
  39. 39.What is the smallest whole number by which 250 must be divided to get a perfect cube?
  40. 40.What is ∛15625? =

Answer key

  1. 7
  2. 2
  3. 13
  4. 16
  5. 9
  6. 8
  7. 5
  8. 4
  9. 6859
  10. 15
  11. 17
  12. 4
  13. 3
  14. 27
  15. 11
  16. 216
  17. 512
  18. 13
  19. 125
  20. 18
  21. 14
  22. 1000
  23. 5
  24. 8
  25. 10
  26. 27
  27. 343
  28. 6
  29. 343
  30. 4913
  31. 3
  32. 9
  33. 22
  34. 2
  35. 216
  36. 125
  37. 27
  38. 21
  39. 2
  40. 25

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