Stanford Pre-Collegiate University-Level Online Math & Physics courses are not your typical self-paced online classes. Once enrolled in a course, students proceed through the materials at their own pace, while there are set windows within which the midterm and final exams must be taken. Ungraded practice problems are available on the learning platform, and for some courses there are also graded homework assignments. Students typically spend 8-12 hours per week on each course. Students’ learning is supported by live online sessions which follow along the posted schedule, though students are free to ask questions from any segment of the course. For large enrollment courses (usually XM511, XM521, XM522, XP645, and XP670) there are dedicated course sessions, while low enrollment courses have a common office hour each week. The precise times for the online sessions, which usually take place between 1 - 6pm Pacific Time, are fixed at the start of each term. Recordings of these sessions are available to students. Proctored exams are the assessments. All students receive Stanford Continuing Studies credit.