easy way is to set it up as a proportion. For example 1/4 is what as a percent?
1/4 = P/100. What is P? If yoy don't see it right away, "cross multiply" to solve for P.
So, 4P = 100 => P = 25 Answer 25%
By definition 25% MEANS 25 per hundred which is of course 1/4 or 1 per four.