Fractions on my texas tI-83

Hello,
You get access the command by pressing [MATH][1: |->Frac].
If you want enter a fraction and keep it as a fraction (albeit a reduced one)
key in the number then the sequence [MATH][1: |->Frac]., then [ENTER].

Practice : 27/48 [MATH][1: |->Frac] [=] gives the reduced form 9/16.
While this fraction is still in [ANS] memory, you can press [MATH][2: |->Dec] [=] to get the decimal value 0.5625
Hope it helps.