Nancy C. Jordan is Principal Investigator of the Number Sense Intervention Project (funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development) as well as the Center for Improving Learning of Fractions (funded by the Institute of Educational Sciences). She is author or coauthor of many articles in mathematics learning difficulties and has recently published articles in Child Development, Journal of Learning Disabilities, Developmental Science, Developmental Psychology, and Journal of Educational Psychology. Dr. Jordan holds a bachelor's degree from the University of Iowa, where she was awarded Phi Beta Kappa, and a master's degree from Northwestern University. She received her doctoral degree in education from Harvard University and completed a postdoctoral fellowship at the University of Chicago. Before beginning her doctoral studies, she taught elementary school children with special needs. Dr. Jordan served on the Committee on Early Childhood Mathematics of the National Research Council of the National Academies.