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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 640 · 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 648 must be multiplied to get a perfect cube?
  2. 2.What is 8³? =
  3. 3.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  4. 4.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  5. 5.What is the smallest whole number by which 2 must be divided to get a perfect cube?
  6. 6.A big cube of edge 3 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 1512 must be divided to get a perfect cube?
  8. 8.What is the smallest whole number by which 192 must be divided to get a perfect cube?
  9. 9.What is 4³? =
  10. 10.What is ∛8? =
  11. 11.What is 9³? =
  12. 12.What is ∛9261? =
  13. 13.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  14. 14.Which of these is a perfect cube? (a) 441 (b) 343 (c) 402
  15. 15.What is the smallest whole number by which 675 must be multiplied to get a perfect cube?
  16. 16.What is 6³? =
  17. 17.Which of these is a perfect cube? (a) 2100 (b) 2154 (c) 1728
  18. 18.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  19. 19.Which of these is a perfect cube? (a) 104 (b) 67 (c) 64
  20. 20.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  21. 21.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  22. 22.What is 12³? =
  23. 23.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
  24. 24.What is the smallest whole number by which 432 must be multiplied to get a perfect cube?
  25. 25.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  26. 26.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
  27. 27.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  28. 28.What is ∛343? =
  29. 29.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  30. 30.What is the smallest whole number by which 81 must be multiplied to get a perfect cube?
  31. 31.What is 10³? =
  32. 32.Which of these is a perfect cube? (a) 1331 (b) 1369 (c) 1549
  33. 33.What is ∛125? =
  34. 34.Which of these is a perfect cube? (a) 134 (b) 125 (c) 160
  35. 35.Which of these is a perfect cube? (a) 553 (b) 512 (c) 669
  36. 36.What is the smallest whole number by which 864 must be multiplied to get a perfect cube?
  37. 37.What is 19³? =
  38. 38.What is ∛5832? =
  39. 39.What is 16³? =
  40. 40.What is the smallest whole number by which 108 must be divided to get a perfect cube?

Answer key

  1. 9
  2. 512
  3. 16
  4. 64
  5. 2
  6. 27
  7. 7
  8. 3
  9. 64
  10. 2
  11. 729
  12. 21
  13. 10
  14. 343
  15. 5
  16. 216
  17. 1728
  18. 19
  19. 64
  20. 13
  21. 216
  22. 1728
  23. 3
  24. 4
  25. 5
  26. 12
  27. 6
  28. 7
  29. 216
  30. 9
  31. 1000
  32. 1331
  33. 5
  34. 125
  35. 512
  36. 2
  37. 6859
  38. 18
  39. 4096
  40. 4

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