In this article, we explore Whitehead's claim that experience is fundamentally affective. We do so in the context of an Italian primary school classroom featuring the use of the multitouch application "TouchCounts." We study the way in which the children and the iPad take each other up and the meanings of number and arithmetic that emerge as a result. In particular, we show that colour, containment and movement play an important role in their experience of number as decomposable and composable through addition.