This article discusses the resolution of a mathematics exercise of the large-scale evaluation of the More Literacy Program, performed by a student with autism in collaboration with the regular teacher and the intern. It starts from the problematic of educational policies that advocate education for all but culminates in the standardization of developmental assessment due to the initial diagnosis of disability. The study is based on the cultural-historical theory of human development, whose understanding of disability is not in what the subject lacks, but in the possibilities arising from the socio-historical-cultural environment. The investigations took place during the 2019 school year in a municipal school of basic education, in the second year of primary schools, with an 8-year-old student diagnosed with autism, with the fictitious name Miguel. The cut brought is from an exercise of the official evaluation of the Program, performed by the student in collaboration with the teacher and the intern. Classroom situations were analyzed in the light of the microgenetic approach of cultural-historical nature, recorded through photography and field diary. The results point to the resolution of the evaluative task in collaboration, which allowed the student with autism to participate in the task that was common to all in the room. They also revealed the need to think of a more democratic and collaborative school. In the final considerations, some indicators of the student's development are listed with focus on discussions about the man and the social function of the school present in the cultural-historical theory.