Supplement: For example, 10 1 is politics, 20 1 is English, and 30 1 is mathematics. In addition, due to different names, other professional courses are basically formulated by various schools, and there is no other special meaning.
10 1, 20 1, 30 1 which subject does the first digit indicate? 1, 2, 3 are national subjects, and 30 1-304 are mathematics1respectively.