have/get (something) down pat
To learn, master, or understand something perfectly, to the point of requiring little or no focus to do, recall, or accomplish it. Make sure you practice these equations until you have them down pat.
Is it down pat or packed?
Down pat is correct. It means it is some response (audible or physical) that is done without having to think about it. ( ie. a "pat answer"). Down "packed" is what "axed a question" is to "asked a question".
What does I got it down pat mean?
to know something so well that you can say or do it without having to try or think: I'd given the talk so many times I had it down pat.
