While the literature makes explicit the importance of high self-efficacy to suc-cess in mathematics, less is known about how to go about achieving it. For example, how are the mastery experiences that are considered an important source of self-efficacy in mathematics created? By elaborating Cristina’s own experiences in prob-lem solving, we plan to add to that body of research. More specifically, using Bandura’s four sources of self-efficacy as a lens to explain Cristina’s experiences in mathematics, we can offer insight into specific mechanisms which contributed to her change in self-efficacy