Numeracy has been shown to play a vital aspect in the lives of all adults and has relevance to work, personal, and citizenship roles. While there is general consensus about the importance of numeracy, little is known about the role of numeracy in the lives of adults with intellectual disability (ID), and whether they continue to develop their numeracy knowledge and skills into adulthood. The aims of this study were to first explore how adults with ID encounter and engage with numeracy in everyday contexts, and second, to investigate ways of supporting and enhancing numeracy for these adults as they participated in different activities.Two theoretical models underpin this study. These the Numeracy Model (Goos, 2007) and the Biopsychosocial Model of Disability (Engel, 1977). The Numeracy Model was originally designed to make visible the numeracy demands of learning in various subject areas, and to alert classroom teachers to the numeracy skills that students studying that subject need to acquire. It was adopted for this study to identify and support numeracy learning at work and during community activities of adults with ID, as numeracy behaviours for this population are typically not well understood nor supported.The conceptualisation of disability as defined by the Biopsychosocial Model of Disability (Engel, 1977) positions individual experiences of disability as complex interactions between biological aspects (such as cognitive impairment), psychological aspects (such as a person’s values and beliefs) and social aspects (such as opportunities and accessibility). When viewed from this perspective, disability is just another dimension of diversity to be supported and celebrated within the community. The Biopsychosocial Model of Disability made visible aspects of the learning contexts in this study and how these shaped learning experiences for a small group of adults with ID. These models were extended to develop a coherent framework to guide the explorations of numeracy in the daily activities of the adults. The cases investigated in this study were four adults with ID engaging in everyday activities where there were opportunities for them to use numeracy. A qualitative approach was used to collect data using observations and interviews over two phases of data collection. The first phase, the Observation Phase, documented current numeracy behaviours and skills demonstrated by the participants during everyday activities which included a range of numeracy demands for each participant. These data were analysed using coding based on the two models framing this study, and the results were used to design individualised numeracy learning goals. In the second phase of the study, the Intervention Phase, design research methodology was used to design tools and the means of proactively supporting each participant’s numeracy development within these activities. These were designed, trialled, and revised in the process of supporting participants’ numeracy learning.There are two main contributions from this study. First, the empirical evidence indicated that all the participating adults with ID already used a variety of mathematical knowledge and skills in everyday activities and had positive dispositions towards further numeracy development within those activities. All participants demonstrated progress in their numeracy learning that was of interest and importance to them. This suggests that for adults with ID in general, further research in this area may lead to benefits in supporting the numeracy development and providing opportunities for learning. Additionally, as two of the participants had Down syndrome, further research in this area may benefit the research and support efforts focused on this specific population. Second, the two models that frame this study supported understanding of the rich interactions between different elements of numeracy, and the impact of disability on participant engagement and navigation of the numeracy demands of the everyday activities, in these contexts. This study adapted design research methodology to the field of adults’ numeracy education, and provided evidence that attending to participant dispositions, needs, and wants within each activity could be leveraged to develop individualised designs which could support positive, meaningful changes to the numeracy behaviours of adults with ID. With individually designed goals and tools to support learning, these adults with ID were able to complete higher numeracy demands of the various activities within each context. In addition, for two of the participants, when this improvement was witnessed by others, it led to access to further opportunities for numeracy learning in similar contexts. Hence, appropriately designed, individual numeracy goals have the potential to provide research evidence that can support changes in perceptions of the abilities of adults with ID by those in the fields of education and community service provision. Finally, the findings related to numeracy learning designs highlight the need for the provision of systematic support and tools to enhance numeracy participation for adults with ID in their current everyday activities and which have potential to improve numeracy learning in this population.