The COVID-19 pandemic led to closures of university campuses around the world from March 2020 onwards. With little or no time for preparation, lecturers turned to emergency remote teaching to continue to educate their students. Online mathematics education poses particular challenges in terms of both the hardware and software necessary for effective teaching, due to issues with mathematical symbols and notation, among others. In this paper, we report upon an online survey of 257 university mathematics lecturers across 29 countries, which explores what hardware and software they used for emergency remote teaching, for what purposes they used these and what training and support were made available to them at the time. We also consider what approaches they took to emergency remote teaching and what were their reasons for this.