Let's see if we can use mathematical formulae in this blog. Inline equations should work like this: $E=mc^2$, while centered equations should work like this:
$$
\label{eq:se}
\left[ -\frac{\hbar^2}{2m} \nabla^2 +\hat{V}(\mathbf{r}) \right] \psi(\mathbf{r}) = E \psi(\mathbf{r}).
$$
Equation $\eqref{eq:se}$ is, of course, Schrödinger's equation. Equation numbers don't seem to work for some reasons, but equations do.
