In the 1980s, it was different to teach unitary equations. Compared with the mathematics in the same grade now, the mathematics in the 1980s has different knowledge points and different learning depth. No matter from knowledge points or knowledge points to expand the depth of training, there is no way to compare mathematics in the 1980 s with mathematics today. At that time, the average math ability of high school graduates was the highest compared with that of students in Grade Three or Grade One last semester.