Actually, Maria understood the way Paula and Pedro were thinking and induced a process of negotiation of what percentage means. This dialogue was rather useful for both students and later shared with the whole class. In particular, Maria became aware this was a much more effective learning experience for Paula than what could be achieved through formal teaching Maria feels this moment illustrates an evolution in her practice: the ability to seize the opportunity whenever it comes. She says: “That’s it! All this concern is the net result of our work [in the project]” (M22)