Learning theories in general ask questions about how pupils – or people in general – learn. But exactly how and under which circumstances does the learning of the fundamentally new occur? To focus on this question, learning environments with core topics of mathematics and computer science are examined. Today, computer science is not a topic that is taught in primary schools in Germany. In the focus of digitalization, this topic and its connection to mathematics will play an important role in future curricula, making it an interesting object of investigation. The paper presents an ongoing study that examines, how the topic of computer science connected to mathematics learning can be approached in primary schools and what and how meanings are negotiated. The focus will be on the question, what roles consensus and dissent play in interactional processes of negotiation and how the learning of the fundamentally (Miller, 1986) new occurs in collective argumentation between pupils.