Ann McCoy is an associate professor of mathematics education at the University of Central Missouri where she teaches mathematics content and methods courses for prospective elementary and middle school teachers. Prior to teaching at the university, she taught elementary and middle school mathematics for twenty-two years. She has been actively involved in numerous professional development projects for mathematics teachers. Joann Barnett is retired from the Ozark, MO, school district where she taught elementary and middle school mathematics for nearly thirty years. She is now an adjunct instructor for mathematics and mathematics education at Missouri State University and Ozarks Technical Community College. Over the past thirteen years, she has been involved with various state and federal grants to provide professional development for teachers. Emily Combs is in her fourteenth year as a middle school mathematics teacher at Clinton Middle School, Clinton, MO. Over the past ten years she has participated in many professional development projects including her role as co-principal investigator of a Mathematics and Science Partnership Grant. She is interested in using learning trajectories to build accessible, mathematically rich lessons to deepen mathematics understanding smoothly across grade levels