It depends. Very complicated and tedious variants can be omitted, regular and commonly used formulas must be written completely, and some formulas can be simplified, such as congruent triangles's judgment theorem; Edge theorem is abbreviated as SSS；; The edge theorem can be abbreviated as SAS；; Corner theorem can be abbreviated as ASA；; The corner theorem can be abbreviated as AAS. Mathematics is a subject that studies concepts such as quantity, structure, change, space and information. Mathematics is a universal means for human beings to strictly describe and deduce 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.