%% 
%%  An UIT Edition example
%% 
%%  Example 04-01-1 on page 32.
%% 
%%  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{201.70511pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\setcounter{equation}{0}
\renewcommand\theequation{4.\arabic{equation}}
\StartShownPreambleCommands

\StopShownPreambleCommands
\begin{document}
\begin{equation}
\begin{array}{@{} rcl @{}}
\mathrm{right} & \mathrm{centre}
  & \mathrm{left} \\[10pt]
 a & b & c                     \\\hline
 1 & 2 & 3                     \\\cline{2-3}
 A & \multicolumn{2}{|c|}{B C} \\\cline{2-3}
\end{array}
\end{equation}
\end{document}