[nilkn]

I was a math major in college only a few years ago, and lower-level courses tended to concentrate most of the grade in exams for this reason. The exams were always pencil-and-paper only, with no resources of any kind allowed. In upper-level classes, the trend often shifted, with most or even all of the grade coming from problem sets. Some classes didn't even have exams. But this is because the material had become entirely proof-based. Referencing books was not only allowed but encouraged.