Preservice elementary teachers tend to have higher mathematics anxiety than other undergraduate majors, which can be mitigated through building self-efficacy. Teacher education programs can address this deficit through methods courses that provide opportunities for preservice teachers to construct mathematical concepts and practice instruction. For this study, the self-efficacy preservice teachers felt about teaching mathematics was assessed before and after completing a one-credit elementary education mathematics seminar. The course included research into student errors, open-ended mathematics tasks, and student reflection. The pre- and post-test data indicated that a statistically significant increase in self-efficacy, t(49) = 11.393, p < 0.05, with qualitative analysis of responses corroborating the positive effects of the course, especially of the student error analysis.