Errors in math mode

Question

I have trouble setting up the math mode. It doesn't matter if i use \begin{equation} ... \end{equation} or \[ ... \] etc, it always gives me the same error. Only having a formula within the text with $ ... $ works, but I would like to use the math mode.

Here's my example:

\usepackage{amsmath}

\begin{document}

\begin{equation}

y = 5

\end{equation}

\end{document}

The errors I'm getting are the following:

• Missing $ inserted
• Display math should end with $$
• Bad math environment delimiter. \end{equation}
• You can't use '\eqno' in vertical mode. \end{equation}
• Missing $ inserted. \end{equation}
• Display math should end with $$. \end{equation}

Thank you very much in andvance!