Abstract
In mathematics lessons we often come across situations in which a teacher considers their pupil's answer wrong if it deviates from the expected answer. In the best case the teacher admits they do not understand their pupil's thinking and do not discard the answer as wrong.
However, even in this case they refuse to communicate about it any further. The fear of misunderstanding pupils often becomes an obstacle to initiation of class discussions.
The paper focuses on the phenomenon of misunderstanding in the teacher-experimenter - pupil interaction. The data come from two experiments.
The analysis of the data clearly shows that the misunderstanding is not caused by the pupil but by the teacher in the role of the experimenter. This finding is a strong motivation to study the phenomenon of misunderstanding in classroom interaction in further research.