Don't waste time obsessing over this problem. Reading quickly is the key. Change at most one version, the examples and exercises have changed, and the knowledge points and outlines are still the same. Do you think the teachers who give questions like to change books? Maybe they use version 5 or even lower, or they don't need to read books when giving questions. Tongji's books only lay the foundation, and only by reading the whole book can you get high marks.