Whole-class discussion of open mathematics tasks is an instructional practice K-12 mathematics educators report has the potential to engage all learners. Because this practice has not been extensively and systematically researched, this study aims to describe and analyze the engagement and experience of learners in open mathematics tasks. Drawing on a holistic conceptualization of engagement with behavioral, cognitive, affective, and aesthetic dimensions, the study specifically analyzes the engagement of three elementary preservice teachers as they participated in tasks and accompanying discussions in their elementary mathematics methods course. The three preservice teachers were selected because of their varied mathematical identities. While the engagement of the three focus preservice teachers varied, results suggest the openness of the tasks was an important factor in making their engagement possible. [For the complete proceedings, see ED657822.]