Question: I would like to have the words 'to mean' and the following mathematical statement to be on the same straight line. Thank you very much! 

```
    \documentclass[11pt,a4paper]{article}
    \usepackage{blindtext}
    \usepackage{mathtools}
    \DeclareMathOperator{\sgn}{sgn}
    \begin{document}
    \begin{flalign*}
    3=+1+1+1
    \end{flalign*}
    to mean
    \begin{flalign*}
    (+1+1+1)=+1+1+1,
    \end{flalign*}
    \end{document}

```

Answer: 
your code should be

```
\documentclass[11pt,a4paper]{article}
\usepackage{mathtools}
\begin{document}
\begin{align*}
3 &=+1+1+1   \\
\intertext{to mean}\\
(+1+1+1) &=+1+1+1,
\end{align*}
\end{document}

```

![intertextalign](https://i.stack.imgur.com/yRM0g.png)
```
\documentclass[11pt,a4paper]{article}
\usepackage{mathtools}
\begin{document}
\begin{align*}
3 =+1+1+1 & \qquad \quad to~{} mean & (+1+1+1) =+1+1+1,
\end{align*}
\end{document}

```

![intertextalign1](https://i.stack.imgur.com/7qrX4.png)