Motivation – In this paper we discuss the beginning of a research project into the design of user interfaces for Computer Algebra Systems (CASs). Research approach – Findings/Design – We begin to examine a theoretical framework describing how people learn problem-solving skills. We also briefly discuss a field study we conducted. Research limitations/Implications – The field study, while small and preliminary, allowed us to see some areas where students ran in to difficulty using Maple. The theoretical framework we begin to outline should help us understand the cause of some of those difficulties. Originality/Value – We begin to better understand how people use CASs to learn mathematics. We also begin to combine Cognitive Load Theory and the Skills-Rules-Knowledge framework. Take away message – This is the beginning of a research project that should help us better understand how CASs can be better designed to assist with learning and the problem-solving process.