Dr. Frederik Dilling is a research associate at the department of mathematics at the University of Siegen. His research focuses on digital technologies and interdisciplinarity in mathematics education and mathematics teacher training. Dr. Felicitas Pielsticker works at the University of Siegen in the department of mathematics as a lecturer and researcher. Her research focuses on a holistic cognitive and neurofunctional description and analysis of mathematical knowledge development processes with digital technologies.Prof. Dr. Ingo Witzke is professor for mathematics education at the University of Siegen. His research group investigates mathematical knowledge development processes of learners interacting with (digital) tools and resources.