Math boo-boo

So when my professor asked me to read the `Know This' about combinations and permutations in class I was startled to see exclamation marks all over the page. At first I wondered if they are there to emphasize a number/letter and was tempted to read it with the appropriate inflections. As impressed as I was to find out that Math actually has an emotional side I played it safe, reading it as: "N exclamation and 2 exclamation blah, blah, blah..."

For ten minutes, no one laughed, corrected me or interrupted. When I was done my prof. explained in his sing song voice that "actually, in mathematics, the exclamation mark is called a factorial and has a value etc. etc."

I'm still looking for a place to bury my head in after that fiasco(: