This paper explores the ways preschool teachers orchestrate instructional environments to promote mathematical play related to early number and, how they intervene during play to promote children's engagement with early number. We highlight these practices to identify resources for the growing numbers of early childhood teachers. This is important as many prospective and practicing teachers do not have access to the knowledge of teaching that supports young children's math learning because of the constraints of mathematics methods courses and the dearth of research on early childhood mathematics in mathematic education journals -- particularly in-depth attention to early number and teaching mathematics in play. [For the complete proceedings, see ED583989.]