These 48 Signs Are Oddly Specific Yet Entertaining

This was a question in an English exam, and given how grammatically incorrect most of the sentences are, we can only assume the goal is to circle the grammatically correct phrase. But the fifth sentence is way too specific. Why math specifically? Why put the glasses under a tree? Why the math teacher’s glasses?

This has to be related to an incident at this school. Maybe some cheeky kid whose worst subject is math thought that if the teacher couldn’t read the exam, they would cancel it. But why hide the glasses under a tree, where many people may find it? I don’t see (pun not intended) how that works.