When choosing a methodology for the teaching-learning process of logical-mathematical thinking, the possibilities available to the teacher are immense. The Montessori method is known for being based on freedom and spontaneous activity, as well as for the characteristic material used. The main objective of this research is to show the pedagogical possibilities of the Montessori method for the learning of the logical-mathematical competence in Second Cycle classes of Preprimary Education. Participants were 39 children. Three didactic activities based on the Montessori method were designed for the purpose of the study, and the instrument used to gather information was a Likert scale check list composed by a number of measurable items related to addition, subtraction, and operations on inequalities. The results of the study encourage both practicing and future teachers to apply the Montessori method in the classrooms as it is an attractive methodology for preprimary students and motivates them to learn contents. It can be concluded that endless contents can be developed with this method, not only logical-mathematical ones, but also any aspect that can be dealt with in the classroom.