Supervised Teaching Practice (PES) should promote the development of skills associated with the profile of the teacher-researcher, namely: observation, recording, analysis, reflection. At the same time, it should provide children with rich and diverse experiences that produce education for (with) citizenship. The research project developed at PES was based on the European project UKIDS (Erasmus +) and was based on learning by project methodology, allowing for interdisciplinary knowledge. The challenges set in the project offer a variety of tasks to work on aspects such as initiative, motivation and innovation, as well as, trust and responsible social participation. Specifically, the Trash Value challenge, proposes to give a new life to waste, respecting a sustainable environment. Based on the implementation of this challenge and using the egg cartons, it was investigated how this material potentiated the development of social skills, reasoning and mathematical communication of children in the 4th year of schooling. The research methodology had characteristics of action-research, selecting different techniques and instruments for data collection. In addition to the pre-test and post-test carried out on the students and the teacher in charge of the class, audio recordings, field notes, photographic records and children's productions were collected and organized in the form of multimodal narration. After conducting the study, it was possible to verify that the Trash Value challenge promoted the development of social skills, with a greater focus on cooperation, self-control and responsibility. Convergingly, problem-solving and mathematical communication skills have improved considerably, in an environment rich in children's environmental awareness.