This paper analyzes how the teaching of fractions is coordinated between primary and secondary education. It examines the possibilities and limitations of promoting understanding based on didactic configurations and content delivery. Utilizing a qualitative approach with a descriptive-interpretive scope, a cross-sectional type, and a case study design, group interviews were conducted with eight teachers from three primary schools and one secondary school. Additionally, regular classroom activities and curricular guidelines were analyzed. The results show consensus regarding priority contents, indicators of comprehension, and teacher perceptions. However, misalignments are identified in the resources used, the representations employed, and the recognition of student difficulties. The findings demonstrate that while primary-secondary articulation in the teaching of fractions is actively advocated for in discourse, proposals, and regulations, gaps still remain in practice.