"Let's Count" is an early mathematics program that has been designed by The Smith Family and the authors to assist educators in early childhood contexts in socially disadvantaged areas of Australia to work in partnership with parents and other family members to promote positive mathematical experiences for young children (3-5 years). A longitudinal evaluation of "Let's Count" was undertaken in 2012-2014 involving 337 children in two treatment groups and 125 children in a comparison group. This paper shares preliminary results from the evaluation. Overall the findings demonstrate that "Let's Count" was effective. [The research reported in this paper was funded by The Smith Family and the Origin Energy Foundation as part of the "Let's Count Longitudinal Evaluation."]