Interesting entry, I liked the story and that you had to be really fast to put stuff in.
Some stuff you could look into;
Maybe put fog on the math questions so that the player can only see it once they click the input bar. This makes it possible for players to read normally, and have a timer on the math stuff.
When I quit the story aspect I wanted to just type right away, but the input isnt focussed yet, fairly easy to do but really handy for players.
The math questions were always the same, so after a while I just wrote the answers down to put them in later, maybe randomize this (and maybe make it a bit easier).
Either way, pretty fun entry ^^