The object of mathematical research is not the "objective" world, but,

First, there is abstraction from the objective world-the field of applied mathematics;

Second, it is completely the product of the human brain, the world created by the human brain, such as number theory, abstract algebra, real variable function and so on.

Therefore, the quantitative relationship in the objective world is only a part of the source of mathematics, while the quantitative relationship and spatial relationship in the purely abstract world are the essence of mathematics. It is said that pure mathematicians strongly disapprove of applied mathematicians.

By the way, mathematics is not a real science, because it cannot be falsified, such as Godel's incomplete theorem.