Aiming interdisciplinary and considering the difficulties in the process of teaching and learning, this paper has articulated a methodological proposal between Biology and Mathematics, developed by two groups of 4th year of Basic Education of public and private institutions in Brazil, where activities have been conducted using laboratory practice of Sciences. The use of Allium cepa as a strategy method in the study of fractions, measurement, and graphics has made possible the observation and recording of data, developing scientific reasoning and also providing manipulative skill development. The results obtained in this study are encouraging and relevant, given that the laboratory activity has been of great benefit in science learning for students. Compared to the results, we can still see that the application of Allium cepa test, through the development of mathematical models, has triggered significant changes in both the teaching position as the learner.