# [Tex/LaTex] Show equation number only once in align environment

alignequations

I want the equation number to be shown only at the last line, or better, somewhere in the middle of all. So instead of (1), (2), ... only (1).
I use \begin{align} ... \end{align}

You can use the split environment from the amsmath package:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{align}
\begin{split}
a &= b \\
&=c \\
&=d \\
&=e
\end{split}
\end{align}

\end{document}