To find out which fraction is the least and which fraction is the greatest you can change all the fractions to have a single denominator. For instance, 1/2 becomes 4/8, 1/4 becomes 2/8 and 5/8 would stay the same. 2/8 is the least, 4/8 is in the middle and 5/8 is the greatest. Threfore, 1/4 is the least, 1/2 is the second least, and 5/8 is the greatest.