A proof is more than just a collection of true statements: it is a means of communication. And in a classroom it is also a demonstration of knowledge. Even if e

A proof is more than just a collection of true statements: it is a means of communication. And in a classroom it is also a demonstration of knowledge. Even if every step is technically correct, the presentation may not be sufficient for full marks. Depending on the class, we may or may not have high expectations for a proof. Also I don't believe the students ever once made this setup but remarked that the steps were reversible, but I would give that full points with a little note that it could be better organized. I've never encountered a formal "do these steps to make a proof" document. I'd have to see it, but it could be a good idea.