Monitoring students' work in the classroom has been recognized as one of the key factors for successful teaching since only a good real-time assessment enables the teacher to give proper and timely feedback. However, it is not an easy task to systematically supervise what students do in the classroom. It also might consume a considerable amount of teachers' resources. This paper presents a work in which computer technology is used in classrooms by students working on electronic worksheets on their. We explore the possibilities of assessing students' work during classroom by automatically analyzing the structure of the documents and the changes along time while students work on them. An experiment is described, showing the system is able to give the teacher valuable information. This information is intended to assess the students' performance and provide them with proper feedback. © 2014 Springer International Publishing.