Mathematical fitting refers to constructing a function as an approximate model according to a set of data obtained, so as to use this function model to predict the corresponding data. The general practice of the high school mathematics fitting problem you mentioned is the least square method. If you are a liberal arts student, you can look at the statistics and regression analysis of the elective course 1-2 published by People's Education Press, and introduce the detailed methods with examples. Regression analysis of science students' choice of 2-3. In addition to fitting, advanced mathematics and interpolation are all methods of mathematical modeling. If you are interested, you can look at the related series of mathematical modeling and mathematical experiments in universities.