Cathy Fosnot is a leading voice in mathematics education. She is Professor Emerita of Education at the City College of New York and the founder of Mathematics in the City, a national center for professional development located at the college. In 2007 she established New Perspectives on Learning to devote her time to speaking around the world, fostering school change through professional learning and support, and producing new resources and materials. Watch Cathy talk about the importance of context in math. Follow Cathy on Twitter @ctfosnot Bill Jacob is a Professor of Mathematics at the University of California, Santa Barbara. In addition to his mathematical research, he develops and teaches courses for pre-service teachers. He is coauthor with Catherine Fosnot of Young Mathematicians at Work: Constructing Algebra and has been a collaborator with Mathematics in the City for twelve years.