In this paper, the second of three classroom-based pilots, the FoNS framework was applied to two year one lessons, one from Russia and one from Poland, both of which exploited the number line in children’s learning. The results, as shown in the table below, highlighted both similarities and differences in the two teachers’ emphases. Both used the number line to encourage *number recognition*, *systematic counting* and *different representations of number* in every reported episode of their lessons. However, Olga in Russia also emphasised the *relationship between number and quantity*, something that Maria in Poland did not. Also, Olga exploited the number line more than Maria with respect to simple *arithmetical operations*, while Maria was the only one to focus on number patterns. However, while the two lessons proved amenable to a FoNS-related analysis, a key difference between the two lessons lay in how the two teachers interacted with both the number line itself and their students. Olga not only encouraged her children to work publicly at the board but also to engage children bodily in their work with the number line, something that Maria did not. Olga’s activities were unrelated to any real world, which Maria’s were. In neither sequence of episodes was observed *quantity discrimination* or *estimation*. Full details of the tasks employed by the two teachers, which offer interesting and very different opportunities for students to acquire FoNS-related competences can be found in the actual paper.