Stochastic calculus is the name for a set of calculations you can do with numbers that involve randomness. It’s like regular calculus, but instead of dealing with numbers like we usually do, we deal with random numbers. Random numbers are numbers that come out of nowhere and don’t follow a pattern. For example, you might roll a six-sided die and get a random number from 1 to 6. Stochastic calculus helps us figure out what will happen when we take a bunch of random numbers and look at their average.