Background: Educational reforms in mathematics imply a series of changes in teacher training. Some of these modifications accentuate the inclusion of new content, the development of mathematical abilities, skills, or competencies, and the implementation of different teaching and assessment strategies, and the use of technology. Primary and secondary education teachers must be able to respond adequately to these curricular standards. In Costa Rica, mathematics education has undergone changes to promote various cognitive processes in students, such as those of number representation. Objectives: The article highlights the diversity of representation systems assigned to the concept of number, proposed by a group of Costa Rican preservice Primary Education teachers, as a promoting agent for the development of processes of representation in students. Design: Theoretically, the research is structured around proposals for the analysis of the meanings of mathematical concepts as associated to teacher training. It is a descriptive study based on an intrinsic case study. Data collection and analysis: The information was collected through a questionnaire. Information analysis highlights the existence of different forms of representation and the justification arguments that the participants apply for their selection; content analysis was used as the analytical technique. Setting and participants: The study was carried out with 23 preservice Primary Education teachers. Results: The results reveal a trend in the use of representation systems of the same form to present the concept of number, particularly iconic and symbolic-numeric representations. Conclusions: A connection is observed between the proposed representations and situations and contexts that seem to be familiar to Primary Education students; this relation deserves further exploration.