Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 715 · 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 ∛12167? =
2. 2.Which of these is a perfect cube? (a) 248 (b) 286 (c) 216
3. 3.What is ∛216? =
4. 4.What is 13³? =
5. 5.What is 16³? =
6. 6.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
7. 7.What is 15³? =
8. 8.What is ∛4913? =
9. 9.What is the smallest whole number by which 108 must be multiplied to get a perfect cube?
10. 10.A big cube of edge 20 cm is cut into small cubes of edge 4 cm. How many small cubes are there?
11. 11.What is ∛5832? =
12. 12.What is the smallest whole number by which 16 must be multiplied to get a perfect cube?
13. 13.A big cube of edge 12 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
14. 14.What is ∛4096? =
15. 15.What is ∛27? =
16. 16.What is ∛1331? =
17. 17.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
18. 18.What is ∛729? =
19. 19.Which of these is a perfect cube? (a) 1109 (b) 1172 (c) 1000
20. 20.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
21. 21.What is the smallest whole number by which 7 must be multiplied to get a perfect cube?
22. 22.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
23. 23.A big cube of edge 6 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
24. 24.A big cube of edge 10 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
25. 25.A big cube of edge 4 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
26. 26.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
27. 27.What is 12³? =
28. 28.What is 10³? =
29. 29.What is 5³? =
30. 30.What is 9³? =
31. 31.Which of these is a perfect cube? (a) 657 (b) 512 (c) 635
32. 32.Which of these is a perfect cube? (a) 30 (b) 27 (c) 48
33. 33.What is ∛125? =
34. 34.What is 17³? =
35. 35.A big cube of edge 8 cm is cut into small cubes of edge 2 cm. How many small cubes are there?
36. 36.What is 2³? =
37. 37.Which of these is a perfect cube? (a) 3017 (b) 2746 (c) 2744
38. 38.Which of these is a perfect cube? (a) 1371 (b) 1394 (c) 1331
39. 39.What is the smallest whole number by which 3 must be divided to get a perfect cube?
40. 40.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?

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