# bm and siunitx mismatch

With this mwe,

\documentclass{article}
\usepackage{bm,siunitx}

% change nothing to the problem
\sisetup{
detect-weight,
detect-display-math
}

\begin{document}
$\bm{\num{.1}}$
\end{document}


I get this error message

> ! Undefined control sequence.
> <argument> \LaTeX3 error:
A sequence was misused.
l.11 $0<\bm{\num{.1}}$


With this other mwe :

\documentclass{article}
\usepackage{siunitx,bm}

\sisetup{
detect-weight,
detect-display-math,
detect-inline-weight=math
}

\begin{document}
$\num{5}x\bm{5x\num{5}}$
\end{document}


I have the next error message :

! Argument of \__tl_tmp:w has an extra }.
<inserted text>
\par
l.11 $\num{5}x\bm{5x\num{5}}$


And \mathbf doesn't work and makes uggly "x".

\documentclass{article}
\usepackage{siunitx,bm}

\sisetup{
detect-weight,
detect-display-math,
detect-inline-weight=math
}

\begin{document}
$\num{5}x\mathbf{5x\num{5}}$

$\bm{0.1}\quad\mathbf{\num{.1}}$
\end{document}


• Just out of idle curiosity: Why don't you write either \textbf{\num{.1}}? – Mico Feb 20 '18 at 22:26
• I follow the advice given to use \bm with success until now. Nevertheless, \mathbf doesn't work as you can see on my edit. – Tarass Feb 20 '18 at 22:37

You can protect the \num and \SI commands with braces:

\documentclass{article}
\usepackage{bm,siunitx}

\begin{document}

\sisetup{detect-weight = true,detect-inline-weight = math}

$\num{5} \SI{50}{\km}$

$\bm{bob{\num{5}\SI{30}{\km}}}$
\end{document}