Beth L. MacDonald is an associate professor in Early Childhood Mathematics Education in the School of Teaching and Learning at Illinois State University. After completing a Bachelor of Arts degree in Studio Art and Elementary Education (PreK-6) at SUNY Potsdam, Beth taught elementary school for 15 years and served as a K-5 Instructional Specialist for two years in southwest Virginia. In this time, Beth taught in fully inclusive elementary classrooms within Title 1 schools and within all K-5 grade levels. While teaching, Beth completed her Master of Arts in Education degree, with a focus on K-8 Mathematics Education and her Doctor of Philosophy degree, with a Curriculum and Instruction concentration and focus on Mathematics Education, both from Virginia Tech. Her research broadly focuses on PreK-5 students’ development of number, particularly with subitizing activity at the center of this development. Moreover, Beth collaborates often with colleagues who examine teachers’ specialized content knowledge development in mathematics/STEM and collaborates with colleagues who examine marginalized students’ number understanding development. Beth also served as a lead guest editor for Special Issue for the Education Sciences Journal, focusing on STEM in Early Childhood Education.