"Let's Count" is a preschool mathematics intervention implemented by The Smith Family from 2012 to the present in "disdvantaged" communities across Australia. It is based on current mathematics and early childhood education research and aligns with the Early Years Learning Framework. Let's Count has been shown to be effective in enhancing mathematics learning and dispositions of young children, early childhood educators and families through a longitudinal evaluation undertaken from 2012-2015. This paper reports on the development, implementation and evaluation of "Let's Count" and its likely future trajectory.