1 3/8= 11/8 and 2 3/5 = 13/5 because you do for example 3 1/2 as a mixed # you do the whole # times the denomonator which is 6 and that plus the numerator which is 7 and keep the denomonater so its 7/2
A whole is nothing but the denominator being the same as the numerator. You do this so that you can add up the numerators when the denominators are same.
