Using your knuckles to check how many days a month has.

Well you know how your knuckles are up and down right? :3 well the the ones that are up are months with 31 days and the ones that are down are days with 30 days with the exception of febuary. Since the up and down knuckles are alternate you can check lol I'm such a nerd :3

Yeah, how do you do that? "/

how'd you do that ?