For perspective there wasn't much engagement in the D.buzz/DIY project contest either. I hope that doesn't ruin the chances for a second round of that contest.
Maybe once in a while instead of a daily contest you can have a one or two week long contest. Possibly something in which users try to come up with their own Hive-themed math problem with solution. That way each user can work with the level of math they are most comfortable with. I'd probably write a short story mystery that requires math to identify the criminal.😎