The students' basic understanding of the content of the lesson videos is assessed through online quizzes and reinforced through online homework.  Students complete homework and quizzes through the WeBWorK online homework system, which is designed to give students instant feedback so that they can self-assess their understanding and correct errors immediately after they occur.  Since it is vital that students watch the lesson videos, instructors can use quizzes to track "attendance," if necessary.  WeBWorK automatically grades homework and quizzes, and the system stores the scores for easy download.