We present a detailed account of interactional mechanisms that support participation in STEM disciplinary practices as an adult and a child explore a technology-enabled embodied learning environment for mathematics. Drawing on ethnomethodological studies of technologyrich workplaces, we trace the process of transforming a vague reference into a mutually available mathematical object: a covariant variable. Our analysis reveals that this mathematical object is an interactional achievement, configured via a reciprocal process of instructing one another's attention. In particular, we demonstrate how participants' explicit responsiveness to indexical and multimodal resources achieves this object.

We present a detailed account of the interactional work between a programming instructor and a middle school student that leads to the resolution of an elusive error in the student’s code. By tracing the fine details of how this resolution came to be, we demonstrate how learning to debug in face-to-face interactions resembles a process of enskilment.