What is the common denominator for five eights, one third and one half

Simple, just write the lists of multiples in the numbers

5/8
1/3
1/2

2:2,4,6,8,10,12,14,16,18,20,22,24
3:3,6,9,12,15,18,21,24
8:8,16,24

Thus, the common denominator would be 24.

5/8*3=15/24
1/3*8=8/24
1/2*12=12/24

These are your fractions.