How to create a table (like tabular) with only equations

Question

I am trying to create a table containing only equations. Similar to a tabular environment. I want to be able to set margins in the table like you can in tabular, but there doesn't seem to be a simple way of doing this without going through each entry and specifying maths mode with $.$. Is there something like the following which produces what I describe?

\begin{mathtable}{|c|c|c|}
\hline
2\pi     & \phi     & \eta   \\
\sqrt 2  & \lambda  & \sigma \\
\hline
\end{mathtable}