There are two main ways to solve "mathematical expectation": just multiply each column of numbers in the distribution table and then add them up. If x is a discrete random variable, all its possible values are a 1, a2, …, an, …, and the corresponding probabilities are p 1, p2…, pn, …, then its mathematical expectation is e (x) = (a1) * (p/kloc. If X is a continuous random variable and its probability density function is p(x), then the mathematical expectation E(X) of X is equal to the integral of function xp(x) in the interval (-∞,+∞). In probability theory and mathematical statistics, mathematical expectation (or simply mean, or expectation) is the sum of the possible results multiplied by the results in each experiment, which is one of the most basic mathematical characteristics. It reflects the average value of random variables.