Karen S. Karp is a professor in the School of Education at Johns Hopkins University. Previously, she was a professor of mathematics education in the Department of Early and Elementary Childhood Education at the University of Louisville, where she received the President’s Distinguished Teaching Award and the Distinguished Service Award for a Career of Service. She is a former member of the board of directors of the National Council of Teachers of Mathematics (NCTM) and a former president of the Association of Mathematics Teacher Educators (AMTE). She is a member of the author panel for the What Works Clearinghouse Practice Guide on assisting elementary school students who have difficulty learning mathematics for the U.S. Department of Education Institute of Educational Sciences. She is the author or coauthor of approximately 20 book chapters, 50 articles, and 30 books, including Elementary and Middle School Mathematics: Teaching Developmentally, Developing Essential Understanding of Addition and Subtraction for Teaching Mathematics, and Inspiring Girls to Think Mathematically. She holds teaching certifications in elementary education, secondary mathematics, and K–12 special education.