1340.96+3236.8+693.6
Just use the calculator on the home page here and type it in exactly as you've written it.
.
wow 10 points.
$${\mathtt{1\,340.96}}{\mathtt{\,\small\textbf+\,}}{\mathtt{3\,236.8}}{\mathtt{\,\small\textbf+\,}}{\mathtt{693.6}} = {\mathtt{5\,271.36}}$$
