Dr. Amy J. Hackenberg taught mathematics to middle and high school students for 9 years in L.A. and Chicago, prior to earning a Ph.D. in mathematics education from the University of Georgia. Amy is currently an associate professor of mathematics education at Indiana University-Bloomington. She conducts research on how middle school students construct fractions knowledge and algebraic reasoning and on how teachers can learn to develop productive student-teacher relationships. In her current project she is investigating how to differentiate instruction for diverse middle school students (see https://idream.sitehost.iu.edu/), studying her own teaching as well as working with practicing teachers. She is the proud co-author of the Math Recovery series book, Developing Fractions Knowledge.