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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 644 · 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 108 must be divided to get a perfect cube?
  2. 2.What is 7³? =
  3. 3.What is 3³? =
  4. 4.What is the smallest whole number by which 1125 must be divided to get a perfect cube?
  5. 5.A big cube of edge 4 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 3125 must be divided to get a perfect cube?
  7. 7.What is 15³? =
  8. 8.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
  9. 9.What is ∛64? =
  10. 10.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
  11. 11.Which of these is a perfect cube? (a) 1977 (b) 1728 (c) 2093
  12. 12.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  13. 13.What is the smallest whole number by which 3 must be multiplied to get a perfect cube?
  14. 14.What is ∛6859? =
  15. 15.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  16. 16.What is ∛8? =
  17. 17.Which of these is a perfect cube? (a) 1188 (b) 1000 (c) 1025
  18. 18.Which of these is a perfect cube? (a) 371 (b) 343 (c) 408
  19. 19.What is ∛3375? =
  20. 20.What is ∛5832? =
  21. 21.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  22. 22.What is ∛8000? =
  23. 23.What is ∛27? =
  24. 24.What is the smallest whole number by which 1080 must be multiplied to get a perfect cube?
  25. 25.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
  26. 26.Which of these is a perfect cube? (a) 2276 (b) 2690 (c) 2197
  27. 27.A cube has a volume of 4096 cubic cm. How long is each edge (in cm)?
  28. 28.A cube has a volume of 343 cubic cm. How long is each edge (in cm)?
  29. 29.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
  30. 30.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  31. 31.What is the smallest whole number by which 2 must be multiplied to get a perfect cube?
  32. 32.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  33. 33.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  34. 34.What is 16³? =
  35. 35.What is ∛512? =
  36. 36.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
  37. 37.What is 8³? =
  38. 38.Which of these is a perfect cube? (a) 3486 (b) 4037 (c) 3375
  39. 39.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  40. 40.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?

Answer key

  1. 4
  2. 343
  3. 27
  4. 9
  5. 64
  6. 25
  7. 3375
  8. 8
  9. 4
  10. 11
  11. 1728
  12. 5
  13. 9
  14. 19
  15. 13
  16. 2
  17. 1000
  18. 343
  19. 15
  20. 18
  21. 5
  22. 20
  23. 3
  24. 25
  25. 19
  26. 2197
  27. 16
  28. 7
  29. 4
  30. 64
  31. 4
  32. 216
  33. 216
  34. 4096
  35. 8
  36. 18
  37. 512
  38. 3375
  39. 10
  40. 12

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