Commutator of $E$ and $t$

Again use the crutch of keeping a wave function on the right to avoid mistakes.

$$\begin{eqnarray*}[E,t]\psi(x,t)&=&\left(i\hbar{\partial\over \partial t}t-ti\hba... ...rtial\over \partial t}\right)\psi(x,t)\\ &=&i\hbar\psi(x,t)\\ \end{eqnarray*}$$

Removing the wave function, we have the commutator.

$$\bgroup\color{black} [E,t]=i\hbar \egroup$$