%%
%% The LaTeX Companion, 3ed
%%
%% Example 3-3-18 on page I-168 in "Basic number and unit formatting".
%%
%% 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}
\setlength\parindent{0pt}
%StartShownPreambleCommands
  \usepackage{siunitx}
%StopShownPreambleCommands

\begin{document}
  \num{123456789011}  \hfill \num{123}        \\
  \num{10001}         \hfill \num{10 001}     \\
  \num{0.000005}      \hfill \num{0,123}      \\
  \num{.05}           \hfill \num{-,05}       \\
  \num{9.95e-3}       \hfill \num{9,95 d-3}
\end{document}