Three. One to get the punchline, and one to point out the math is wrong.
He pointed outside and said "The ATM machine" c/o /u/jubileo5
Pupil: Well if I could there wouldn't be much point in me being here!
The mirror
It's a rough crowd...Ba da bum chssh
Don't worry, he'll tell you
A meme-oir
Katie Keurig. (I know the setup might need some work but I just like the punchline I made up.)
A short one with no punchline
It has so many problems! -Sorry doing a whole bunch of math today and i thought of this.
Because it gives them square roots