Mathematics specialists play a significant, meaningful, and integral role in supporting elementary school teachers in this mathematically connected world. These teacher leaders (coaches, resource teachers, math leads, and so on) work closely with all members of the school community--students, teachers, and administrators--and have a range of responsibilities that span working with individual teachers to working with groups of teachers and their students several times each week and sometimes daily. In this article, the authors highlight one of many responsibilities that a particular mathematics specialist, Ms. Sneider, has on any given day. Sneider was working with a group of fifth-grade students who did not seem to understand that the like fractional parts that compose a whole item must be of equal size. By posing the funky cookie task, she hoped to start a conversation about this important concept with her students, probe their thinking, and increase their understanding of fractions. The funky cookie example gives a snapshot of the types of instructional decisions that mathematics specialists might make in their daily work. The example also highlights the rich mathematical content that specialists must draw on when working with students. Sneider used her mathematical understanding to make important decisions that in turn furnished additional learning opportunities for her students. At the outset, Sneider had not intended to address the equal-size concept. Although she had a planned activity, she made a spontaneous decision to change it. Listening to her students' ideas, she realized that she needed to address a misconception they had about fractions. Math specialists must be extremely flexible, think quickly on their feet, and make moment-to-moment decisions with multiple students at different grade levels throughout a school day. (Contains 4 figures and 1 table.)