I don't always think of specific numbers, but for example in SSHE i memorized the basic probablilities of certain draws hitting, etc. In the middle of a hand (since I have a weak head for hard math on the fly) I rarely whip out the calculator, but I will compare my chance of hitting vs. what the pot is laying me. There won't be a moment where you realize "THat math based decision saved me money!" You'll just realize, "Hey, I would've tilted away those bets calling when I shouldn't have."