Paola Sztajn is a professor of mathematics education at North Carolina State University and is a principal investigator in Project AIM (All Included in Mathematics). Daniel Heck is vice president of Horizon Research, Inc. in Chapel Hill, North Carolina, and is a principal investigator in Project AIM. They are co-authors with Kristen Malzahn of Activating Math Talk: 11 Purposeful Techniques for Your Elementary Students.