Saw this joke on the xkcd forums today posed by Pippin:

Two of my friends in math class today:

“Dude, our slope is so undefined!”

“Straight up, bro.”

Spoiler hint: What is the slope of a horizontal straight line?

Another one from that forum:

Why don’t jokes work in base 8?

Because 7 10 11.

JakeSpoiler hint: What is the slope of a straight VERTICAL line?

ReginaThe spoiler hint was the funniest part. ðŸ™‚

mathfailI fail.