The COVID-19 pandemic has had an impact on learning and teaching mathematics in many countries. In Germany, as in other countries, the measure of distance learning was taken. We consider the use of digital mathematics textbooks with integrated digital tools to be particularly suitable for remote or distance learning. The potentials of digital mathematics textbooks, such as assessment, interactivity or collaboration possibilities address the challenges teachers faced in distance learning. Whether mathematical learning processes can also be initiated among students during distance learning is investigated in this study using achievement tests. For this purpose, students in distance and classroom learning who have completed the same series of lessons on conditional probability and authentic contexts are compared. Results from the pretest-posttest design are presented.