Although there are existing methods for solving linear congruence ax ≡ b (mod n), finding solutions still remain difficult especially when the modulus n is large. Thus, this paper aimed to develop a linear congruence solver that will provide step by step solutions even for large modulus n. The linear congruence solver was based on alternative numerical method devised by the researcher and was developed using Microsoft Visual Studio C# programming language. The system was tested using ISO 9126 standard questionnaire for software quality characteristics such as functionality, reliability, and usability. The result of the evaluation shows that the developed linear congruence solver is highly functional, highly reliable and highly usable. The use of linear congruence solver as an instructional aid for instructors and students is highly recommended.

mathematics, number theory, linear congruence ax ≡ b (mod n), developmental research method, ISO 9126 software quality characteristics