The paper describes a study that examined the impact of two teaching approaches "focus on correctness" and "discuss errors" on secondary students' solutions to algebraic inequalities. Two groups of 10th graders were taught by two experienced teachers, Corry and Era, who followed their different didactical beliefs about the use of errors in classroom discussions. Both groups studied according to the same curriculum during an identical time frame and answered the same problem-sets on the same days. We found that students in the "discuss errors" group performed significantly better in solving most inequalities. We believe that additional and more extensive studies, examining this issue are needed.