Drawing on research in the context of Swedish school-age educare and adopting a post-humanist theoretical--methodological approach, we put forward the notion of mathemat-ing to conceptualise mathematical events that emerge in out-of-school configurations of practice. In them, ethical sensibilities as affects of engagement and rejection may be mobilised. Being responsive in the event together with other human and non-human is argued to be a valuable experience of importance for children's overall mathematics education. Mathemat-ing contributes a more inclusive view of what it may mean to relate to mathematics.