Abstract. Expressing generality, recognising and analysing patterns and articulating structure is a complex task and one that is invariably problematic for students. Nonetheless, very few systems exist that support learners explicitly in the process of mathematical generalisation. We have addressed this by developing a novel environment that supports users in their reasoning and problem-solving of generalisation tasks. We have followed a stakeholder-centred design process, integrating feedback and reflections from twenty-four children, five teachers and a variety of other stakeholders. This paper focuses on several inter-related design issues that have been informed by this iterative process and demonstrates how the system can be used for a typical generalisation task to foster an appreciation of generality and indeed algebra.