The purpose of this paper is to investigate the relationships between adult students' mathematical micro-identities (informed by positioning theory) and their mathematics (informed by radical constructivism). I used positioning theory to conduct a detailed turn-by-turn analysis of students' micro-identities, and to inform my models of students' mathematics. Results showed how positive micro-identities can promote persistence, vulnerability, visibility, or flourishment in students' mathematics. Implications for research and practice are discussed. The latter connects to the PMENA conference theme by highlighting the type of classroom environment teachers can foster to engage their students and maximize opportunities for learning. [For the complete proceedings, see ED658295.]