Being able to effectively interpret students' thinking and respond effectively in the moment are important skills that preservice teachers (PSTs) need to learn. This study zooms in on 14 PSTs' planning, teaching, and reflections involved in number string lessons, and investigates to what extent PSTs anticipate their students' strategies and incorrect answers. Further, through a lens focused on PSTs' talk moves, we explore how PSTs supported students' understanding of the strategies and concepts, and handled incorrect answers and unanticipated responses (strategies). Results show that PSTs were capable of anticipating many answers and strategies but need more improvement in making full use of various talk moves in their questioning. Implications are provided for mathematics methods instructors to plan activities to better support PSTs. [For complete proceedings, see ED581294.]