Numeracy is important for everyday life. Being numerate has a positive impact on the quality of life of individuals, with positive economic, health, and social outcomes. Despite this, little is known about the role of numeracy in the lives of adults with intellectual disability (ID). Design research has been used to develop ways to support mathematical learning for typically developing students. This study investigates the use of design research to develop context-specific, physical tools to support adults with intellectual disability to improve their numeracy capabilities and engagement in daily tasks. Using observation and interview data, findings demonstrate increased engagement and participation in the numeracy demands of these tasks. Participants reported positive perceptions of improved competence and independence. This study demonstrates the application of design research to the field of numeracy for adults with intellectual disability, and the usefulness of designing context-specific tools to support their numeracy development and independence.