Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 789 · 40 sums

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.

1. 1.What is the smallest whole number by which 49 must be divided to get a perfect cube?
2. 2.A big cube of edge 24 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
3. 3.Which of these is a perfect cube? (a) 512 (b) 690 (c) 699
4. 4.What is 7³? =
5. 5.What is the smallest whole number by which 864 must be divided to get a perfect cube?
6. 6.What is 9³? =
7. 7.What is 13³? =
8. 8.What is ∛1331? =
9. 9.What is the smallest whole number by which 4 must be multiplied to get a perfect cube?
10. 10.Which of these is a perfect cube? (a) 388 (b) 441 (c) 343
11. 11.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
12. 12.A cube has a volume of 1728 cubic cm. How long is each edge (in cm)?
13. 13.What is 20³? =
14. 14.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
15. 15.What is ∛13824? =
16. 16.What is 14³? =
17. 17.Which of these is a perfect cube? (a) 248 (b) 323 (c) 216
18. 18.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
19. 19.What is 11³? =
20. 20.Which of these is a perfect cube? (a) 3050 (b) 2744 (c) 2950
21. 21.What is the smallest whole number by which 16 must be divided to get a perfect cube?
22. 22.What is 10³? =
23. 23.A big cube of edge 15 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
24. 24.What is the smallest whole number by which 25 must be multiplied to get a perfect cube?
25. 25.What is 15³? =
26. 26.What is 12³? =
27. 27.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
28. 28.A cube has a volume of 1000 cubic cm. How long is each edge (in cm)?
29. 29.A cube has a volume of 1331 cubic cm. How long is each edge (in cm)?
30. 30.What is 5³? =
31. 31.A cube has a volume of 5832 cubic cm. How long is each edge (in cm)?
32. 32.Which of these is a perfect cube? (a) 1796 (b) 1853 (c) 1728
33. 33.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
34. 34.Which of these is a perfect cube? (a) 164 (b) 125 (c) 173
35. 35.What is 18³? =
36. 36.Which of these is a perfect cube? (a) 749 (b) 729 (c) 933
37. 37.What is the smallest whole number by which 9 must be multiplied to get a perfect cube?
38. 38.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
39. 39.What is the smallest whole number by which 54 must be multiplied to get a perfect cube?
40. 40.What is ∛125? =

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