CGI professional development (PD) is designed to enhance teachers’ ability to teach math for understanding by increasing teachers’ understanding of children’s mathematical thinking. The content focus is Operations and Algebraic Thinking and Number and Operations in Base Ten as described in the Kindergarten through Third Grade Common Core State Standards for Mathematics (CCSSM). Through a focus on children’s thinking, teachers improve their ability to engage students in the Standards for Mathematical Practice described in CCSSM. CGI PD develops teachers’ ability to use any curriculum to teach math for understanding.