Question: How to set the column width in the align environment.
I've got a align environment to demonstrate how to do division by hand so the columns always contain only one number, but the columns are much wider than this.

Following an example only showing the ugly result because of to wide columns:

```
\begin{align}
    &1&2&3&4&4\\
    & & & &2&4\\
\end{align}

```

Answer: 
```
\usepackage{array}

\newenvironment{enumalign}
  {\par\addvspace{\topsep}\setcounter{enumi}{0}
   \noindent$\begin{array}{@{}r@{\hspace{\labelsep}}r@{}>{{}}l@{}}}
  {\end{array}$\par\addvspace{\topsep}}
\newcommand{\eitem}{\stepcounter{enumi}\makebox[\labelwidth][r]{\theenumi.}&}

\begin{document}
\begin{enumalign}
\eitem 1+1&=2\\
\eitem 1&=2-1
\end{enumalign}

```

Remember to end the rows with `\\`
```
\documentclass{article}
\usepackage[fleqn]{amsmath}

\begin{document}
\begin{flalign} % Displays all equation #'s in environment.
1 + 1 &= 2 \\
1 &= 2 - 1 &
\end{flalign}
------------------------------
\begin{flalign*}% Add the * if you want no equation #'s displayed.
1 + 1 &= 2 \\
1 &= 2 - 1 &
\end{flalign*}
------------------------------
\begin{flalign}
1 + 1 &= 2 \notag \\% \notag used if you want to specify equation #'s
                    % only for certain equations. 
1 &= 2 - 1 \\
3 + 4 &= 7 \notag \\
4 &= 7 - 3 &
\end{flalign}

\end{document}

```

Results below: 

![Align](https://i.stack.imgur.com/EYucu.png)