Kevin Desmond, an MIT professor and professional poker player, teaches a 43-minute lecture on poker theory that's been viewed by ten million people. The core lesson is absurdly simple: a single equation determines when to go all-in. You estimate three things—the probability your opponent folds (fold equity), the probability you win if called (showdown equity), and the payoffs—multiply each by its outcome, add them together, and commit everything if the result is positive. That's it. Wall Street prop trading desks pay $250,000 a year to hire MIT graduates who can execute this math faster than markets move. The real insight is that this equation applies far beyond poker. Every binary commit-or-fold decision in life—quitting a job, launching a company, proposing marriage, betting on a trade—reduces to the same three inputs. Julius Caesar spent months calculating the probability of victory, payoff, and cost of loss before crossing the Rubicon in 49 BC. The math was clear, so he committed completely. Professional traders on Wall Street run this arithmetic on every position and never half-shove or half-fold. Retail traders, meanwhile, hover between two half-decisions and lose to both. The lecture is free on MIT OpenCourseWare with problem sets online. Millions have watched it. Almost none have actually written those four inputs above their desk before making a real all-in decision. The math itself isn't the edge. The willingness to finish the calculation before you actually bet everything is.