This article presents a new teaching methodology implemented on a basic mathematics course for Engineering students at the Open University of Catalonia (UOC). The experience of its implementation in the 2010/11 academic year is described and the results are discussed. This methodology is based on formative assessment. As well as doing the activities contained in the course materials, students take weekly practice and assessment quizzes and receive automatic feedback. Not only are they told whether their answers are correct, but they also receive suggestions and comments on the possible sources of their errors. The results suggest that this teaching methodology gives students the opportunity to regulate their own learning processes while allowing lecturers to identify and react to problems in a responsive, timely manner. They also suggest that it fosters interaction among students and between students and lecturers. Moreover, since the teaching methodology was introduced, the number of students dropping out of the subject has fallen considerably.