Class 8 Maths Worksheet: Cubes and Cube Roots

Maths worksheets lesson 59: Cubes and cube roots · Set 21 · 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.Which of these is a perfect cube? (a) 803 (b) 859 (c) 729
2. 2.A big cube of edge 4 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
3. 3.What is 17³? =
4. 4.What is ∛2197? =
5. 5.What is ∛2744? =
6. 6.A big cube of edge 12 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
7. 7.A cube has a volume of 27 cubic cm. How long is each edge (in cm)?
8. 8.What is ∛125? =
9. 9.What is 8³? =
10. 10.A cube has a volume of 125 cubic cm. How long is each edge (in cm)?
11. 11.A cube has a volume of 2197 cubic cm. How long is each edge (in cm)?
12. 12.What is ∛343? =
13. 13.What is 13³? =
14. 14.Which of these is a perfect cube? (a) 145 (b) 159 (c) 125
15. 15.A cube has a volume of 6859 cubic cm. How long is each edge (in cm)?
16. 16.What is 14³? =
17. 17.What is the smallest whole number by which 40 must be multiplied to get a perfect cube?
18. 18.A cube has a volume of 2744 cubic cm. How long is each edge (in cm)?
19. 19.Which of these is a perfect cube? (a) 3895 (b) 3416 (c) 3375
20. 20.What is ∛1331? =
21. 21.Which of these is a perfect cube? (a) 1672 (b) 1621 (c) 1331
22. 22.A cube has a volume of 64 cubic cm. How long is each edge (in cm)?
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 ∛27? =
25. 25.Which of these is a perfect cube? (a) 216 (b) 308 (c) 250
26. 26.What is 2³? =
27. 27.What is 16³? =
28. 28.What is ∛4096? =
29. 29.Which of these is a perfect cube? (a) 343 (b) 451 (c) 422
30. 30.What is ∛1000? =
31. 31.A cube has a volume of 8 cubic cm. How long is each edge (in cm)?
32. 32.What is 11³? =
33. 33.What is ∛216? =
34. 34.What is 18³? =
35. 35.A cube has a volume of 3375 cubic cm. How long is each edge (in cm)?
36. 36.What is 20³? =
37. 37.A big cube of edge 6 cm is cut into small cubes of edge 1 cm. How many small cubes are there?
38. 38.A cube has a volume of 512 cubic cm. How long is each edge (in cm)?
39. 39.A big cube of edge 18 cm is cut into small cubes of edge 3 cm. How many small cubes are there?
40. 40.A big cube of edge 3 cm is cut into small cubes of edge 1 cm. How many small cubes are there?

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