%%
%% The LaTeX Companion, 3ed
%%
%% Example 9-6-15 on page I-720 in "Vertical positioning features".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{135.0pt}

  %!TEX program = lualatex

  \setlength\parindent{0pt}

%StartShownPreambleCommands
 \usepackage{fontspec} \setmainfont{Erewhon}[Fractions=On]
 \setsansfont{Lato}[Fractions=On]
 \setmonofont{IBM Plex Mono}[Fractions=On]
%StopShownPreambleCommands

\begin{document}
           1/2 2/3 47/11 1/1000  but note: a/b 1/n\par
 \sffamily 1/2 2/3 47/11 1/1000 okay here: a/b 1/n\par
 \ttfamily 1/2 2/3 47/11 1/1000     a/b 1/n
\end{document}