%% 
%%  An UIT Edition example
%% 
%%  Example 10-07-6 on page 213.
%% 
%%  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}
\usepackage[utf8]{inputenc}
\AtBeginDocument{\setlength\parindent{0pt}}
\setcounter{equation}{14}
\renewcommand\theequation{10.\arabic{equation}}
\StartShownPreambleCommands
\usepackage{amsmath}
\makeatletter
\@fleqntrue\let\old@mathmargin=\@mathmargin\@mathmargin=-1sp
\let\oldmathindent=\mathindent\let\mathindent=\@mathmargin
\newsavebox{\myendhook}     % for the tables
\def\tagform@#1{{(\maketag@@@{\ignorespaces#1\unskip\@@italiccorr)}
  \makebox[0pt][r]{%        % aligned after the line number
    \makebox[0.5\textwidth][l]{\usebox{\myendhook}}}%
  \global\sbox{\myendhook}{}% empty box
}}
\makeatother
\StopShownPreambleCommands
\begin{document}
\sbox{\myendhook}{\footnotesize% save table
\begin{tabular}{@{}ll}
  $a_0$  & Bohr radius ($\mathrm{= 0{,}53\,\mbox{\AA}}$)\\
  $e$    & elementary charge\\
$N_{si}$ & number of silicium atoms\\
         & per unit volume\\
     $m$ & atom mass\\
     $Z$ & atomic number
\end{tabular}}
%
\begin{equation}
\varepsilon = \frac{E\times 4\times\pi\times \varepsilon_{0}
    \times a_0 \times \left( Z_i^{\frac{2}{3}} + Z_{Si}^{\frac{2}{3}}
    \right)^{-\frac{1}{2}}} {Z_i\times Z_{Si}\times e^2\times\left(1+
    \frac{m_i}{m_{Si}}\right)}\,;
\end{equation}
%
\sbox{\myendhook}{abc}
\begin{equation} a^2+b^2 = c^2 \end{equation}
\begin{equation} z = 9 \end{equation}
\end{document}