When discussing problems, I am used to emphasizing the definition and the conditions for the existence of problems; When observing problems, we are used to grasping the relationship among them and further considering the overall situation of multiple factors on the basis of micro-understanding; When we understand problems, we are used to generalizing the existing strict mathematical concepts such as duality, correlation, randomness, universality, nonlinearity, periodicity and chaos. For example, we can see that price is the duality of goods, and benefit is the universal connotation of companies.