Active learning in mathematics can lead to deeper understanding than passively listening to a lecture, yet recent studies indicate that didactic teaching dominates online tutorials. This study investigated student participation in three types of activity: solving mathematical problems via polling, on-screen activities on a shared whiteboard and text-chat, during online undergraduate mathematics tutorials. Data were collected from tutorial observations, student and tutor surveys, semi-structured student interviews and a tutor focus group. Results showed high student participation in all types of activity. Students also perceived them as enjoyable and aiding their learning, though with some differences between the types of activity such as those done by text-chat being slightly less well received. Perceived benefits to students' learning included the ability to attempt similar activities, with suggested benefits such as correcting misconceptions receiving a more mixed response. By demonstrating the successful use of mathematical activities in synchronous online tuition, these results provide motivation for tutors to facilitate essential active learning online.