This study investigates how 20 prospective elementary teachers make connections among children's multiple mathematical knowledge bases in their thinking about assessing children's understanding of fractions. The researcher facilitated concept-mapping tasks to examine the ways the prospective teachers linked concepts related to children's lives and experiences and children's mathematical thinking. This paper focuses on high-level tasks as a potential entry point to build stronger connections between assessing children's understanding of mathematics and children's multiple mathematical knowledge bases in teacher education. Additionally, I discuss implications for teacher educators and considerations for further research. [For the complete proceedings, see ED583989.]