The research part of a fraction to develop argumentative competition in fourth grade had as a general objective to determine the development of argumentative competition in fourth grade students, through the Strengthening their cognitive linguistic skills, while solving a series of tasks, from the part everything relationship. The methodological approach was qualitative, with descriptive, three instruments were used for the collection of information: Instrument 1 Inquiry, Instrument 2 didactic Unit and instrument 3 Final Test. In the final analysis, it was evident in the responses of the students a more frequent use of linguistic cognitive skills as explanation, justification and argumentation, also noticed an increase in the arguments located in Levels 2 and 3. According to the results, it is possible to think that by strengthening the cognitive linguistic skills of the students, it is able to improve their argumentative competence.