rag math

Calculating when your period is going to be to plan for future vacations.

Bob: Hey, let's go camping for Labor Day weekend.
Katie: hmmm, hang on let me look at the calendar. *counting weeks*
Bob: what are you doing?
Katie: Rag math! Gotta make sure Aunt Flo won't be visiting before I agree to the trip.

by Biggins McGee August 31, 2016