Online learning is a solution in dealing with a pandemic in the field of education so that knowledge and skills using digital technology are a necessity that pre-service mathematics teachers were must-have. Mastery of applications that support mathematics learning is also the key to understanding and solving math problems in the digital era which will also be useful for students when teaching at school. The purpose of this study was to describe learning trajectory of students in mastering computer applications that support mathematics learning through video tutorial assignments. The method used is a design research method with preliminary design stages, experimental teaching, and retrospective analysis. The period of this research is four months in a computer mathematics application course. From eleven practicum materials for computer mathematics application courses, in each material, a video tutorial is obtained containing the steps in solving math problems using three types of applications, namely GeoGebra, SPSS, and maple. The developed learning trajectory contributes to the mastery of the application, namely that 81% of students can use the application with various variations of mathematical problems. In addition to producing video tutorial learning products and learning trajectories, this study also provides an overview of students' abilities in taking online learning during the pandemic period.