CLEARLY: I don't want to write down all the in-between steps.
TRIVIAL: If I have to show you how to do this, you're in the wrong class.
OBVIOUSLY: I hope you weren't sleeping when we discussed this earlier, because I refuse to repeat it.
RECALL: I shouldn't have to tell you this, but for those of you who erase your memory tapes after every test, here it is again.
WITHOUT LOSS OF GENERALITY: I'm not about to do all the possible cases, so I'll do one and let you figure out the rest.
THE FOLLOWING ARE EQUIVALENT: If I say this it means that, and if I say that it means the other thing, and if I say the other thing...
BRIEFLY: I'm running out of time, so I'll just write and talk faster.
LET'S TALK THROUGH IT: I don't want to write it on the board because I'll make a mistake.
http://www2.stetson.edu/~efriedma/mathhumor.html contributed by: Mike Brilleslyper, USAFA