She studies how students’ reasoning with integers is constrained and enabled by their current conceptions of addition and subtraction and their ways of operating with counting numbers. She is also studying the interplay between the development of additive and multiplicative reasoning at the middle school level. She teaches a doctoral course on children’s construction of number and works with pre-service teachers at both the elementary and secondary levels in developing effective methods of mathematics instruction. Prior to being a faculty member, she taught secondary mathematics for 6 years.