\input eplain

\obeylines %
This is \frac 1/2 cup.
This is \frac 2/3 cup.
This is \frac 3/4 cup.
This is \frac 5/6 cup.
This is \frac 6/7 cup.
This is \frac 7/8 cup.
This is \frac 8/9 cup.
This is \frac 9/{10} cup.
This is \frac 10/{11} cup.

\end