This paper investigates the effects of Content and Language Integrated Learning, CLIL for short, on both the attainment of the subject matter, mathematics in our case, hence the content aspect of CLIL. The second axes of research focuses on the effect of CLIL on the learners' proficiency vis-à-vis the language of instruction, epitomized here by English--hence the linguistic aspect of CLIL education. This paper adopts a multiple approach methodology to deal with the research questions at hand. I concluded on the basis of field work, this includes data coding and analysis, questionnaire design and analysis, an administered mathematical test, and the teacher's continuous assessment of his students, that CLIL education is more effective than traditional educational systems in helping learners to achieve high proficiency levels in the target language (English) and to attain high levels of competence in the subject matter (mathematics). I believe these results might be explained by an existing of a covert tradeoff between the brain mechanisms involved in learning both mathematics and languages as well as by the pedagogical opportunities, provided by CLIL environment, and which echo, to a great extent, L1 acquisition environment.