The science of calculating precisely the amount of drinks one has consumed in a night.
Many formulas also describe how vomit trajectiles become more horizontal and streamlined in ratio to how far away the nearest human, expensive carpeting or uniformed officer are (these are often simply referred to as "targets") or the astronomical numbers that can only be found in bar tabs.
Also, according to the laws of ThirstyDynamics, how many drinks one has already consumed or the mere presence of certain variables (such as "hot chicks") can often cause the amount of drinks consumed to increase up to 10-fold.
"Man, i can't even remember how much we drank last night.."
"well, it was three 30's between 6 people.. that's 15 beers per head! plus the vodka.."
"Yea, I'm a bit asian when it comes to my beerithmatic"
Counting how much money you have, and subtract it from what you started with to figure out how much you drank the night before.
I started the night with $100, beers were $5, and I woke up with $50. Using beerithmatic, I know that I drank 10 beers last night.