There are only 3 1 set for 45 sets of senior high school entrance examinations because there are only 3 1 set. According to the relevant public information: 45 sets of senior high school entrance examination mathematics (2022 edition) selected 202 1 Hubei senior high school entrance examination mathematics real questions, 202 1 local high-quality good papers, big city unified examination papers, famous school joint examination papers, and pre-test high-quality simulation papers. At present, there are only 3 1 set of senior high school entrance examination papers, so the reason is that 45 sets of senior high school entrance examination mathematics are only 3 1 set.