The Common Core State Standards for Mathematics expect students to build on their knowledge of the number system, expressions and equations, and functions throughout school mathematics. For example, students learn that they can add something to both sides of an equation and that doing so will not affect the equivalency; however, squaring both sides can lead to extraneous solutions. For students to make sense of the situations presented in this article, teachers must provide students with a solid foundational understanding of radicals and noninvertible processes. Teachers can help students by being more rigorous in their own algebraic manipulations and explanations and by requiring students to be more precise in theirs. Although plus-minus signs may seem minor at first, they can lead to misunderstandings as students progress in the algebra curriculum. Teachers need to know when to expect these misunderstanding, why they occur, and how they might help students make sense of these situations.