Teacher telling can support but also hinder learning. In inquiry activities, telling that removes productive struggle may be problematic. In this study, different aged students experimented in a digital learning environment to build rules for a balance beam. We examined how the amount of teacher telling vary according to students’ age and the sophistication level of the rule. We collected video data from 21 pre-service teachers when each of them guided eight, 10, and 12 year old students. We found that the amount of teacher telling generally was not related to students’ age. However, when considering teacher guidance for more sophisticated rules, teacher telling was related to students’ age. Thus, the focus of the guidance is an essential factor affecting telling and teachers may have pressure for guiding students towards a high-level product.