The present article originates in research carried out in a private bilingual school of Bogota. Its main objective was to establish the factors that influence the understanding of mathematical concepts and processes, during the application of the strategy preview-view-review, with kindergarden students whose mother tongue is Spanish. This strategy is summarized in three essential steps: use of the mother tongue to introduce subjects, use of the second language to direct activities related to the exposed topic, and use of the mother tongue to summarize main ideas or ask comprehension questions. This study required permanent observation around an intervention, which characterises the design of empirical and quasi-experimental research, and the data taken were qualitative and quantitative (mixed methodology). However, in this document only the quantitative results obtained from the comparison of the participating courses will be presented, which meets one of the objectives of the original research: to analyze and compare the results obtained by the students of the two groups, in the tests administered before, during and after the intervention. It was found that students' performance in the experimental group was significantly better than in the contrast group, which suggests that the use of the mother tongue during the implicit process of acquisition of the second language contributes to the improvement of the academic performance of the students of the experimental group.