Wenn das Unausgesprochene regelnd wirkt – eine theoretische und empirische Arbeit zum Impliziten

This article introduces a concept that will help to make explicit those elements which are often tacitly „assumed“ in certain rules and terms. The concept refers both to Ludwig Wittgenstein’s model of meaning and use of conceptual terms, as well as to methods of empirical research in the expert/novice paradigm. Putting those concepts into practice is the main focus of the research pre-sented in this article. I analyzed examples of how experts and novices sort fraction equations into different categories as they solve them. My research shows that experts categorize certain fraction equations differently from each other: what some experts see as a reduction, others classify as structuring, reducing or applying a standardized method. In other word, the implicit meaning in these terms is revealed only in the sum of all the experts’ opinions. Compared to novices, experts tend to work more directly towards possible solutions, and tend to look further ahead. What sepa-rated experts from novices is their expertise in “flexible calculation”