Initial seeds for mathematics literacy are planted during early childhood. Children benefit when they are exposed to and provided with opportunities for math experiences that emphasize their holistic development and not just mathematics proficiency in isolation. This way of viewing and presenting mathematics to young children requires teachers who are equipped with strong mathematics teaching skills. This study examined a 21-hour professional development series for public school preschool teachers on early numeracy, geometry, mathematical reasoning, and teaching pedagogies. This professional development series aimed to help preschool teachers incorporate effective mathematical practices and increase their comfort level in teaching mathematics. Participants noted this professional development series impacted their ability to foster children's early numeracy development, engage in "math talk" pose questions that helped children process early numeracy, and contextualize early numeracy through stories and/or word problems. The study demonstrates change takes time, and the impact of this professional development series is dependent on preschool teachers' readiness and their perception of their teaching context needs.