You can easily check whether 5/6 is greater than 1/4 by converting both fractions so they have the same denominator.
The LCD (lowest common denominator) for both 6 and 4 would be 12, so I will be converting both fractions so they have 12 as their denominator.
5/6=10/12 and 1/4=3/12
Because 10/12>3/12, 5/6 is greater than 1/4 as well. Hope this helps :-)