The limitations in access to mathematical resources faced by visually impaired people (VIPs) are undoubtedly one of the most significant obstacles for them to obtain, e.g., a degree in science. In this context, computational tools such as Computer Algebra Systems (CAS) are not blind-friendly, which causes solving elementary mathematical problems to become a challenging task for this group of people. This paper presents the Casvi system, a CAS for people with visual disabilities that allows carried out basics and advanced numerical calculations using the Maxima mathematical engine. Twenty-five VIPs tested the Casvi system to assess its functionality and usability. As a result, VIPs achieved a 92% accuracy when executing mathematical operations through Casvi. Finally, our system outperforms the LAMBDA system regarding the time needed by VIPs to perform mathematical operations correctly.