Night of the living math

This game made me realize I don't know basic math lol

Awesome idea, I loved it :D

Bug:

If I input a result just after dying the "dying audio" get stuck and I have to refresh the page.

Suggestions:

- Keep score of zombies killed

- Show the "house" life percentage ( and also maybe heal it by killing zombies? I'm not sure if this happens because it is not shown)