\usepackage{mathspec} \setallmainfonts(Digits,Latin){Old Timey Mono}
\begin{document}
Just test some equation \begin{equation} \frac{e^x}{2-x} = \int_0^\infty f(x)dx \end{equation}
\end{document}
\usepackage{mathspec} \setallmainfonts(Digits,Latin){Old Timey Mono}
\begin{document}
Just test some equation \begin{equation} \frac{e^x}{2-x} = \int_0^\infty f(x)dx \end{equation}
\end{document}