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Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 121 · 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.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  2. 2.What is 20³? =
  3. 3.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
  4. 4.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
  5. 5.Which of these is a perfect cube? (a) 512 (b) 513 (c) 678
  6. 6.What is 4³? =
  7. 7.What is ∛64? =
  8. 8.What is ∛27? =
  9. 9.Which of these is a perfect cube? (a) 45 (b) 42 (c) 27
  10. 10.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  11. 11.Which of these is a perfect cube? (a) 3459 (b) 3466 (c) 3375
  12. 12.What is 2³? =
  13. 13.What is 6³? =
  14. 14.What is ∛3375? =
  15. 15.What is 8³? =
  16. 16.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
  17. 17.What is the smallest whole number by which 25 must be divided to get a perfect cube?
  18. 18.Which of these is a perfect cube? (a) 216 (b) 247 (c) 284
  19. 19.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
  20. 20.What is ∛12167? =
  21. 21.A cube has a volume of 216 cubic cm. How long is each edge (in cm)?
  22. 22.What is 10³? =
  23. 23.What is ∛8000? =
  24. 24.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
  25. 25.What is the smallest whole number by which 243 must be divided to get a perfect cube?
  26. 26.What is ∛512? =
  27. 27.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
  28. 28.Which of these is a perfect cube? (a) 1344 (b) 1369 (c) 1331
  29. 29.What is the smallest whole number by which 49 must be divided to get a perfect cube?
  30. 30.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
  31. 31.What is ∛4913? =
  32. 32.What is the smallest whole number by which 1944 must be multiplied to get a perfect cube?
  33. 33.What is 16³? =
  34. 34.Which of these is a perfect cube? (a) 1000 (b) 1190 (c) 1088
  35. 35.A big cube of edge 16 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  36. 36.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
  37. 37.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
  38. 38.A big cube of edge 12 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
  39. 39.Which of these is a perfect cube? (a) 729 (b) 730 (c) 935
  40. 40.What is the smallest whole number by which 10584 must be divided to get a perfect cube?

Answer key

  1. 64
  2. 8000
  3. 5
  4. 4
  5. 512
  6. 64
  7. 4
  8. 3
  9. 27
  10. 8
  11. 3375
  12. 8
  13. 216
  14. 15
  15. 512
  16. 2
  17. 25
  18. 216
  19. 5
  20. 23
  21. 6
  22. 1000
  23. 20
  24. 14
  25. 9
  26. 8
  27. 125
  28. 1331
  29. 49
  30. 10
  31. 17
  32. 3
  33. 4096
  34. 1000
  35. 64
  36. 216
  37. 64
  38. 27
  39. 729
  40. 49

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