If the probability of mathematics in the senior high school entrance examination is calculated incorrectly, if the process is correct, about 2 points will generally be deducted. If the previous steps are wrong, more points may be deducted.

Tree diagram: Also called tree diagram. A tree diagram is a graphical representation of a data tree, which organizes objects in a parent-child hierarchy. Is an expression of enumeration. The mathematical probability problems in the senior high school entrance examination are generally handled by listing or drawing a tree diagram. The standard of answering questions is to list all the basic events through a list or draw a histogram, and then find the basic events that meet the meaning of the question to calculate the probability.