Early Learning STEM Australia (ELSA) is a play-based digital learning program for children in preschool to explore the practices that underpin Science, Technology, Engineering and Mathematics (STEM). ELSA apps will go beyond the screen to encourage active play that supports STEM practices, such as exploring location, patterns and problem solving. Here, we outline current research into spatial reasoning apps for mathematics, suggest a pedagogical framework to underpin mathematics learning using mapping as an exemplar, and then explain how we will use a design based approach to create apps that support learning in Mathematics.