Page 60. The first volume of fourth grade mathematics is a compulsory education textbook developed and published by People's Education Publishing House and the Research and Development Center of Primary School Mathematics Textbook Institute. Unit 6, Thinking in the Tree of Wisdom, on page 60. Mathematics is a universal means for human beings to strictly describe the abstract structure and mode of things, and can be applied to any problem in the real world. All mathematical objects are artificially defined in essence. In this sense, mathematics belongs to formal science, not natural science. Different mathematicians and philosophers have a series of views on the exact scope and definition of mathematics.