I don't like when people tell me to "Do the math". I graduated school, I don't have to do math anymore. People only say this when there's no need to do any math like: "I had diarrhea 9 times last week and only bought 3 rolls of toilet paper, you do the math!". People will say "You do the math" even when they're referring to something that doesn't even deal with math like:
"Hey where'd Frank go?"
"He brought two hookers up to his hotel room with a bottle of lube, a tub of Philadelphia cream cheese, and a department store mannequin... You do the math!"
What math is there to do? One dick plus two vaginas, lube, cheese, a plastic human divided by dignity? And why does that phrase only apply to mathematics. You would never say something like "That lemur tried mating with a skunk, you do the zoology and genetics..." When you actually cite the appropriate methods it sounds worse. That's a major sign of a dumbass saying.