The overarching interest of this study concerns how to outline learning opportunities and support in early childhood education (ECE) without losing its play-based character. More specifically, the study reports an empirical investigation into the evolving activity of a 6.5-year-old child and an adult conversing about the child's drawing of "Numberland." What the child's drawing and his discussion about it with the adult tell us about his emergent mathematics skills is analysed. How the child shifts between speaking and enacting "as if" and "as is," and how the adult supports his mathematics understanding through entering into the play-frame are analysed. How imaginary, play-based activities like this can provide the means for ECE and what this implies for the teacher are discussed.