A calculator sounds like a pretty good place to advertise actually. Any tool where a user spends a lot of time instead of rapidly scrolling through it could be decent ad space.
Sure, a calculator. But this isn't really a general purpose calculator. It's a simple question/answer of "number of votes in this district". How long honestly are you going to spend on a site like that? It sounds to me like a very long-tail question. (Admittedly, I've never even felt the urge to ask the question much less search for a web site to answer it.)
