This study has two main research objectives. Its main one is to analyze the origin of a systematic error, made by first year students of the Computer Sciences Degree at the National University of Salta. The systematic error arises when the students are dealing with Numeral Systems. From there, a second objective is to develop teaching procedures leading to recreate the error in a conceptual reconstruction process, within a playful environment. The theoretical framework used is the Brousseaunian concept of epistemological obstacles in the learning process. We use a sample of 152 students. In this article, we propose a strategy that allows real processes of error reconstruction and construction, in order to enable real epistemological progress. Resources within a virtual environment are presented as play and interactive alternatives with the aim of reinforcing the concepts studied in the classroom: videos, educational software and a computer game specifically developed for Numeral Systems.XI Workshop tecnología informática aplicada en educaciónRed de Universidades con Carreras en Informática (RedUNCI)