The study proves that a didactical model based in a method to solve word problems of increasing complexity which uses a numerical approach was essential to develop the analytical ability and the competent use of the algebraic language with students from three different performance levels in elementary algebra. It is shown that before using the analysis ("numerical analysis") comprised in the method, a "preparatory analysis" is required. It was observed that when the use of this analytical process is given sense, the student advances in his/her ability to establish the relationships between the elements of the problem, which central aspect is the numerical equivalence between two quantities that mean the same in the problem. The study also revealed some of the obstacles that obstruct the analytic development. [For complete proceedings, see ED489597.]