Today we were learning about functions. I introduced the concept of "For every input there must only be 1 output" or "Every x maps to exactly 1 y". Suddenly, a girl pipes up.

Student: No cheaters!
Me: Huh?
Student: You know...the x's can't be with more than one y.
Me: Oh, okay. Yeah, no cheating x's. Every x can only have one "y" girl friend.
Student #2: Can y's have more than 1 x?
Me: Yup, that's okay. We're only worried about x's having 1 y.
Student #3 (girl): That's because girls are allowed to have more than one boyfriend. Boys just can't have more than 1 girlfriend. I think I'm going to like this unit.