Mathematics in ancient China was practical, but it stagnated after the Song Dynasty because there was no theoretical basis. However, western mathematics is a pure way of thinking and an abstract tool, which gradually moves towards rationality, so that all we are learning now are western mathematics.
Pure mathematics may be useless for the time being, but it may be useful in a few hundred years. For example, matrix, number theory, group theory, Riemannian geometry, partial differential equations ... were pure mathematical theories at first, but now they are widely used in engineering calculation, cryptography, relativity, astronomy and physics.
Applied mathematics is to find a solution to a problem, including mathematical modeling, operational research, game theory, etc., which are widely used in finance, economy, market analysis, company operation and other fields.
Mathematics is a way of thinking, so mathematics involves all aspects of society.
Among them, complex mathematical theories are often most closely related to physics, information science and computer science, while applied mathematics is closely related to engineering science, economic finance and market management.
For most people, mathematics is a problem-solving tool, which abstracts, models and solves mathematical equations, and restores the obtained results to the results of solving problems.
Only a few mathematicians do theoretical research and provide possible advanced solutions for the future development of science. Quite a few mathematicians have entered the fields of economics and information science. For example, more than half of the Nobel Prize in Economics graduated from mathematics, and a considerable part of the inventor von Neumann (mathematician) in the computer field and the winner of the Turing Prize, the highest prize in the computer field, also came from mathematics.
Of course, a little knowledge of addition, subtraction, multiplication and division is enough to calculate your salary and bonus if it doesn't involve complex problems in natural disciplines such as finance, engineering application, mathematics, physics and chemistry.