This paper reports a study developed with twenty-six students from a 7th-grade class and was carried in the context of teaching experience in the school year of 2016/2017, using an applet, Equation Buster, on the learning of solving single-variable linear equations. The research objectives are to assess how this applet can help students to see the value of isolating the unknown when solving an equation, to visualize the addition and multiplication properties of equality, to discover these relationships from themselves, and to contribute the development of their algebraic thinking. The methodological approach is qualitative with the characteristics of case study research. The results show that using Equation Buster together with the teacher's mediation helps students to learn how to solve equations by applying the properties of equality or/and the rules of solving equations. It was concluded that there was a significant evolution in the students' performance in the area of generalization.