Nafis AMA, Herumurti D. EFFECTIVENESS STUDIES OF THE LEARNING BASIC MATHEMATICAL OPERATIONS ON USERS USING EDUCATION GAMES WITH ESCALATING DIFFICULTY LEVEL IN SEVERAL TYPES OF GAMES. JUTI [Internet]. 2020 Jul. 31 [cited 2025 Oct. 12];18(2):115-24. Available from: https://juti.if.its.ac.id/index.php/juti/article/view/989