Abstract
The purpose of developing an Android-based Gauss Jordan application is as an alternative in effective and practical Linear Algebra learning. The method for developing this research is R&D (Research and Development) research with the ADDIE development model. Data collection techniques used are material validation sheets and application display; practicality sheet; test sheets (pretest and posttest); and student opinion sheets. The application developed in application design is with figma.com and for software development using visual studio code. Questionnaire instruments and questions on systems of linear equations were given to 22 TI21A4 students in the Linear Algebra course. Based on the data that has been obtained and processed, the score for improving student learning outcomes is 0.71 which is considered effective. The improvement is classified as high and includes effective, and the average score of the practicality assessment is 4.2 which is included in the high category. This application also received a positive response from students who have used it, so the Gauss Jordan 3x3 application is suitable for use in learning and determining solutions to linear equations.