Understanding mathematical equivalence is critical for students' success in algebra. Despite its importance, many students misinterpret the equal sign due to early exposure to operational patterns in arithmetic, leading to entrenched misconceptions. This study investigates how feedback can correct these misconceptions through the implementation of an online version of the Improving Children’s Understanding of Equivalence materials. The study used A/B testing to evaluate accumulating and diminishing feedback on second graders’ understanding of mathematical equivalence. Students made significant improvements in equation solving and conceptual understanding across both feedback types, underscoring the value of immediate, elaborative feedback. However, no significant difference was observed between feedback conditions. The present study informs the development of effective instructional interventions for early mathematics education that can be delivered at scale. By refining automated feedback and addressing student-specific learning needs, educators and researchers can strengthen foundational mathematical understanding and better prepare students for future algebraic success.