Previous studies highlight the importance of investigate the construction in video-recorded learning situations. The aim of this study is to investigate how video-recordings can be used to enhance pre-service teachers' abilities to identify children's exploration of mathematics in preschools. Even if some previous studies have focused the use of video-recordings of learning situations to improve teaching, only a few of them focused how constructed videos enhance pre-service teachers' abilities to identify when children explore mathematics through learning-situations in preschool. The participants were pre-service teachers in a higher education course. Data consisted of pre-service teachers' written responses after viewing eleven edited video clips before, during, and after a compulsory mathematics teacher education course. The analysis is based on variation theory and show the impact of the construction of the video clips and how to design the clips to enhance the pre-service teachers' abilities to define mathematical components during the children's activities.