Over 100 students taking part in mathematics bridging courses were asked in a survey about their understanding of ‘assumed knowledge’ for studying mathematics units at university. Further data were obtained by email from 16 students who agreed to further participation. A phenomenographic analysis was carried out on all responses to obtain categories for students’ conceptions of ‘assumed knowledge’. A two dimensional outcome space was proposed, with the categories increasing in complexity and expansiveness on each dimension. One dimension related to students’ understandings about the purpose of ‘assumed knowledge’, while the other pertained to the content or substance of the ‘assumed knowledge’. We termed these aspects the ‘why’ and ‘what’ of ‘assumed knowledge’ conceptions. The results show the diversity of student awareness about ‘assumed knowledge’ ranging from perceiving it as vague and pointless ‘stuff’ to a cohesive body of foundational knowledge for tertiary study. The study provides qualitative data relevant to the debate on prerequisites versus ‘assumed knowledge’ for university entry
