Solve for âXâ Katie Kush and Lily Larimar just canât seem to focus in class, and professor Maximus isnât happy about it. To stop their constant chatter, he seats star student David Lee between them to break up the talking once and for all. But after professor Maximus falls asleep at his desk, the students do much more than talk. In the true fashion of a helpful student, David makes sure Lily and Katie ace their math testâand learn a few other things, too