This article describes an online tutoring system that was used to give preservice teachers an opportunity to analyze and remediate student work. Through a careful analysis and rich discussion about different suggested remediation strategies, preservice teachers were exposed to a variety of techniques that could be used to help correct student errors. The author argues that this online error analysis items challenged preservice teachers to analyze, diagnose, and provide targeted instructional remediation intended to help mock students overcome common error patterns and misconceptions.