The article shows the results of research related to the topic of counting principles and specifically answers the question: What are the processes followed by children in the 3rd grade of preschool related to counting principles that lead them to solve problems? Cognitive processes constitute an essential element of intellectual development from the early stages of training in the development of skills to understand and use numbers in certain contexts. A qualitative methodology was used, using action research and the proposal of Marques P. (2004), for the reflection process. The results show that there is a low level of performance, which reflects the need to generate a specific job, focusing areas of opportunity to create activities that favor them.