Darma IK, Karma IGM, Santiana IMA. Practicality and effectiveness of digital mathematics teaching materials in improving the problem-solving ability for polytechnic students. IRJEIS [Internet]. 2021 Oct. 5 [cited 2026 Jun. 28];7(6):203-1. Available from: https://sloap.org/journals/index.php/irjeis/article/view/1935