This research aims to develop an E-module using a Flip Builder Application Based on Problem Solving in the subject of Taxation for PPH Chapter 23,24,25, 26, and 28(a)/29. was conducted Research Development (R&D) method. The development steps are guided by ADDIE model (Analyze, Design, Development, Implementation Evaluation). stage has 3 stages, namely 1). Validation test which there two val...