The mathematics education research is increasingly focused on different didactical hypotheses for constructing teaching and learning situations involving the decimal principle of the numeration system. One of these situations is, for example, counting a big collection of objects through the tangible manipulation. Within this situation, several problems at different levels arise: the time demanding, the role of the retro-actions and the class orchestration made by the teacher. This paper aims to show how a simulating device can overtake some of these problems related to the type of task “Counting a big collection” implemented in a tangible environment.