This four-part NCTM E-Example features Fraction Tracks, an interactive online game, and illustrates how the playing of mathematical games can foster mathematical communication, motivate students, and engage them in applying concepts and skills. Part one, Playing Fraction Tracks, contains the game applet and information about using the game with students. When playing the game, students must think about how fractions are related to a unit whole, compare fractional parts of a whole, and find equivalent fractions. Part two, The Role of the Teacher, contains video clips that illustrate the communication of mathematics between a teacher and her students. Part three, Communication Among Students, shows how activities like this one allow students to use communication as a tool to deepen their understanding of mathematics. And in part four, Reflecting on Practice, the teacher reflects on her own mathematical learning that occurs in using activities like this game with her fifth-grade students. Each part offers video clips and discussion questions to support teacher professional development. (author/sw/js)