Audio-podcasts offer notable opportunities for oral representation of mathematical content through digital media--not only for teacher education but also in primary schools. This article deals with the process of creating such podcasts, as well as their uses in schools, university teaching and research. We allow for various learning groups--which are made up of university students or school students- to create audio podcasts, either at German universities or schools, for the purpose of strengthening understanding of various mathematical topics. For this endeavour, learners only need a mobile recording device (i.e., smartphone or tablet). Often, learners can even use personal devices for both recording and research of the given topic (BYOD).