%%
%% The LaTeX Companion, 3ed
%%
%% Example 3-3-19 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}
 Use \num{1.2+-3}, \num{1\pm 2} or \num{0.5(2)}. Note that
 \num{0+-1} is, but \num{+-1} is not, an uncertainty value.
\end{document}