This study examines the cognitive understanding of the mathematics of fourth-grade students of SD Negeri Ketanggung Cilacap Regency through video media in remote learning. One part of successful learning is cognitive understanding. It is necessary to use media that can improve students' cognitive understanding in remote learning. Video media is one of the needed media since it may make abstract material concepts more concrete. This research is qualitative and uses a case study approach. This study included fourth-grade teachers as well as fourth-grade students. Observation, interviews, and documentation were the techniques used to collect data. Researchers used source triangulation and technological triangulation to test the data validity. The findings show that students' cognitive understanding was good when they listened to the video media provided by the teacher. Students listening well to video media are engaged in their learning. The results of student evaluations are good, as evidenced by the first observation. Students became less active and their learning results were quite low in the second observation when they did not listen to the video media well. The implementation of remote learning using video media cannot be separated from several supporting factors and inhibiting factors in its implementation.