Sitting in live home games, I can obviously get a quick percentage on hand odds, but pot odds seem to give me more difficulties. I know the theory, but getting that math through the head in a reasonable time is often challenging.

Anyone have any tips or tricks to make these calculations under time pressure? Obviously if it's nice round numbers (ie: 20 bucks in, 5 bucks to you for a call), there is no problem, but often this is not the case.