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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 509 · 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 864 must be multiplied to get a perfect cube?
  2. 2.What is 8³? =
  3. 3.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  4. 4.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  5. 5.Which of these is a perfect cube? (a) 1334 (b) 1331 (c) 1481
  6. 6.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  7. 7.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  8. 8.What is the smallest whole number by which 1600 must be multiplied to get a perfect cube?
  9. 9.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  10. 10.What is the smallest whole number by which 320 must be divided to get a perfect cube?
  11. 11.Which of these is a perfect cube? (a) 30 (b) 49 (c) 27
  12. 12.What is 17³? =
  13. 13.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
  14. 14.What is the smallest whole number by which 375 must be divided to get a perfect cube?
  15. 15.Which of these is a perfect cube? (a) 66 (b) 94 (c) 64
  16. 16.What is 6³? =
  17. 17.What is ∛13824? =
  18. 18.What is the smallest whole number by which 1600 must be divided to get a perfect cube?
  19. 19.What is the smallest whole number by which 200 must be multiplied to get a perfect cube?
  20. 20.What is 10³? =
  21. 21.What is 18³? =
  22. 22.What is 9³? =
  23. 23.Which of these is a perfect cube? (a) 1224 (b) 1000 (c) 1197
  24. 24.What is 16³? =
  25. 25.What is ∛6859? =
  26. 26.What is the smallest whole number by which 108 must be divided to get a perfect cube?
  27. 27.Which of these is a perfect cube? (a) 125 (b) 133 (c) 145
  28. 28.Which of these is a perfect cube? (a) 529 (b) 524 (c) 512
  29. 29.What is the smallest whole number by which 3136 must be divided to get a perfect cube?
  30. 30.A big cube of edge 8 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  31. 31.What is ∛3375? =
  32. 32.What is 19³? =
  33. 33.What is ∛4913? =
  34. 34.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  35. 35.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  36. 36.What is the smallest whole number by which 128 must be divided to get a perfect cube?
  37. 37.What is ∛8? =
  38. 38.What is ∛1000? =
  39. 39.What is the smallest whole number by which 576 must be multiplied to get a perfect cube?
  40. 40.What is the smallest whole number by which 49 must be divided to get a perfect cube?

Answer key

  1. 2
  2. 512
  3. 216
  4. 27
  5. 1331
  6. 125
  7. 216
  8. 5
  9. 14
  10. 5
  11. 27
  12. 4913
  13. 13
  14. 3
  15. 64
  16. 216
  17. 24
  18. 25
  19. 5
  20. 1000
  21. 5832
  22. 729
  23. 1000
  24. 4096
  25. 19
  26. 4
  27. 125
  28. 512
  29. 49
  30. 8
  31. 15
  32. 6859
  33. 17
  34. 125
  35. 5
  36. 2
  37. 2
  38. 10
  39. 3
  40. 49

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