\input{umtest-preamble} \usepackage{mathtools} \usepackage{unicode-math} \setmathfont{XITS Math} \begin{document} \[ \frac{a^2 + b^2}{a^2 + b^2} \frac{\cramped{a^2 + b^2}}{a^2 + b^2} \frac{a^2 + b^2}{\cramped{a^2 + b^2}} \] \( \frac{a^2 + b^2}{a^2 + b^2} \frac{\cramped{a^2 + b^2}}{a^2 + b^2} \frac{a^2 + b^2}{\cramped{a^2 + b^2}} a^{ \frac{a^2 + b^2}{a^2 + b^2} \frac{\cramped{a^2 + b^2}}{a^2 + b^2} \frac{a^2 + b^2}{\cramped{a^2 + b^2}} } a^{ a^{ \frac{a^2 + b^2}{a^2 + b^2} \frac{\cramped{a^2 + b^2}}{a^2 + b^2} \frac{a^2 + b^2}{\cramped{a^2 + b^2}} } } \) \end{document}