Distinguishing multiplication principle problems and permutation problems in the classroom helps us examine common student errors.
Mary C. Caddle, firstname.lastname@example.org, is a researcher and project director at Tufts University in Medford, Massachusetts. Her current work is in teacher preparation and professional development, with a focus on examining teachers' and students' mathematical thinking.
BÁrbara M. Brizuela, email@example.com, is a professor of mathematics education at Tufts University. Her work focuses on K–5 children's learning of mathematics, particularly in the area of algebraic reasoning, and of representations in mathematics.