Formal specifications and reasoning techniques in software modelling are needed to ensure the correctness of the system at the design phase. Event-B is a formal method with support tools that allows the stepwise development of reactive systems. Such systems include multi-agent systems as a subclass. In this paper, we propose an approach to specify capabilities of a number of software agents. We then verify whether these capabilities help the agents to accomplish a certain task using a supported tool for Event-B. We use the binary numeral system as a case study to illustrate our approach.