I went to a larger university, and was in the math department for most of my coursework. My math homework was graded by fellow undergraduate students who received a rubric and selected 4 problems per homework set, out of about 8ish (most classes. A few tough classes only assigned 2-3 proofs or so a week) but the TAs would grade the exams and the professors wouldn’t grade anything. Homework was at most 15-20% of one’s grade, exams being the rest. But most of my professors didn’t care about the homework as it was a tool for learning the material that was on the exams.