%% 
%%  An UIT Edition example
%% 
%%  Example 04-20-4 on page 69.
%% 
%%  Copyright (C) 2010 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{375.57637pt}
\setlength\fboxsep{0pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\StartShownPreambleCommands
\newcommand*\Frac[2]{\displaystyle\frac{#1}{#2}}
\StopShownPreambleCommands
\begin{document}
left\rule{1cm}{.5pt}\fbox{$\Frac{A}{B}$}
\fbox{\raisebox{0pt}[0pt][0pt]{$\Frac{C}{D}$}}
\fbox{\raisebox{0pt}[0pt][1cm]{$\Frac{E}{F}$}}
\fbox{\raisebox{0pt}[1cm][0pt]{$\Frac{G}{H}$}}
\fbox{\raisebox{0pt}[1cm][1cm]{$\Frac{I}{J}$}}
\fbox{\raisebox{1cm}[0pt][0pt]{$\Frac{K}{L}$}}
\fbox{\raisebox{-1cm}{$\Frac{M}{N}$}}\rule{1cm}{.5pt}right
\end{document}