The method of drawing a tree diagram is the same as the list method, but it is presented in two forms, involving at least two main factors. These two methods are based on the study of the simplest enumeration method, and their complexity is more complicated than that of the simple enumeration method, so every possibility should be listed, but the expression is different.

Drawing a tree diagram to find probability can cultivate the order of everyone's thinking, improve students' ability to analyze and solve problems, and make students' thinking more agile through the tree diagram method. The method of drawing tree diagram is an upgrade based on simple enumeration, from which we can get inspiration and solve the more complicated problem of finding the probability of factors involved in this process.

Drawing a tree diagram involves two factors. In order, all possible results should be listed in this order, and then the probability of one of the events should be found.