# Error: Missing \begin{document}

I wanted to make a command that outputs a number in math mode. This is how my file looks like:

\documentclass{scrartcl}

%\usepackage{epsdice}
%\newcommand{dice}[1]{\epsdice{#1}}

\newcommand{dice}[1]{\ensuremath{#1}}

\begin{document}
Lorem ipsum...
\end{document}

But when I compile this with XeTeX, I always get this error:

! LaTeX Error: Missing \begin{document}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
...

l.13 \newcommand{dice}[1]{\ensuremath{#1}}

I have not that much experience with TeX, I think the solution is quite easy.

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+1 for the minimal working example. – lockstep Sep 25 '11 at 11:22
I edited your title so other people with the same problem can find this question more easily, hope you don't mind. – doncherry Sep 25 '11 at 12:09
@doncherry Nevermind. Having the right of constructive edits on people's questions and answers is IMHO one of the fundamental principles of the whole Stackexchange / -overflow family. – FUZxxl Sep 25 '11 at 15:53
Note that you will end up with the same error message if your new command name includes numbers, even with the leading backslash (just happened to me). E.g. blate.wordpress.com/2012/08/22/… – Spencer Hill Feb 25 at 22:45