From Jonnydigital.com, the only reliable source
This is a FAQ to install the 'realcalc' package required by the LaTeX package, 'invoice', under MikTeX for Windows.
A package called 'invoice' for the typesetting program LaTeX requires two other packages to function, 'calc' and 'realcalc'. Unfortunately, 'realcalc' is not available in the MiKTeX package manager due to licensing issues. A manual install is possible but difficult, and a Google search is no help.
You will need to install realcalc manually. First, create a
folder named realcalc in the \tex\generic
subdirectory of your MiKTeX install folder (should be something like
C:\Program Files (x86)\MiKTeX 2.8\tex\generic\).
Next, go to http://tug.ctan.org/tex-archive/macros/generic/realcalc/ and download the file
realcalc.tex. Put it in the realcalc
folder you created. (Windows security settings may prevent you
from downloading directly to this folder, so download it to somewhere
else and copy it in.)
Then, create a text file called realcalc.sty, with
the following contents:
\input realcalc.tex
\endinput
Place this file in the realcalc directory where
you put realcalc.tex.
Finally, and this is an important step, load the MiKTeX settings program (in the Start Menu under MiKTeX 2.8 > Maintainence (admin) > Settings (admin)). Click "Refresh FNDB" (in the General tab, under the "Maintainence" fieldset.)
invoiceBoth invoice and its other prerequisite
calc should be installed already if you did a full
install of MiKTeX. If not, use the MiKTeX Package Manager to install
these.
The documentation for invoice can be found
here.
Note that although the documentation only shows examples between
\begin{invoice} and \end{invoice}, your
document still requires a \documentclass, and both
\begin{document} and \end{document} as
usual. Don't forget to include \usepackage{invoice}
in the preamble.
Page created: 18th March 2010