Eleven Reborn, I Protect Forty-Two

In Class 7, Grade 12, there are fifty-three students, and eleven of them have returned with memories of the future. They remember every exam and every ranking from next year. But none of them can recall who stood at the podium in their past life. On the first day of school, Wen Liang tore up a student's test paper. Not because of cheating, but because the solution to that problem was something he hadn't seen until his second year of graduate school. Among the fifty-three papers in the class, eleven used the same solution—even the extra negative sign was wrong in the same spot, at the upper right of the same letter. He had a red pen in his pocket. When he drew a circle around a name, three lines would appear on the paper: [Shao Lidong · Class 7, Grade 12 · Student ID 41] [Original trajectory: 2026.6.7, did not leave the exam hall] [Current deviation: 0%] He marked them one by one. Eleven names, the same date. Later, he marked all fifty-three—still that same day. These eleven had returned with memories from after that day. The remaining forty-two knew nothing. And they remembered every future event, none of which included this homeroom teacher. This pen could only observe, not change; the ink decreased with each use. There were still 279 days until that day. He decided to get all fifty-three people out of the exam hall, not one missing. — Description from novelcodex.org