When entering the fraction on the calculator, put a parentheses then put in the number press divide, put in the second number, close the parentheses, and do the opperation needed. the press enter. the answer will come out a decimal. press the "MATH" key and hit 1. The calculator Screen will show " Ans>Frac" press the ENTER key and the calculator will put the answer in fraction form.
It is a assumptions that you should use all the fractions functions with all the compitibles values of fraction.
I highly recommended you this ti84 graphing calculator through this calculator you can easily get all the fraction based results of graphing.
Good Luck!