The ability of mathematical communication is the ability of students to express mathematical ideas both oral and written in the form of language, symbols, and mathematical notations that are easier for students to understand mathematical problems. Problem based learning is a learning model that can be used to improve students' mathematical communication. In implementing the Problem Based Learning (PBL) model, teachers need appropriate modules. This study analyzes and designs teaching materials in the form of modules, based on the Problem Based Learning approach, allowing improving mathematical communication skills. The subjects of this study were students of class XI SMK Muhammadiyah 1 Sentolo, Kulonprogo. This type of research is research and development with the ADDIE development model. The collection instruments used were interview guides, classroom observations, and tests. Data analysis uses data reduction, data presentation, and drawing conclusions. This research produces an module needs analysis and module design according to the needs analysis. Modules are designed according to Problem Based Learning (PBL). Modules are designed to improve students' mathematical communication skills. The results of the study can be used as a guide when the teacher develops a learning module for a problem-based learning model. The novelty of this research is the integration of mathematical communication skills into module design.
Keywords Mathematical Communication, Problem Based Learning, Modules DesigN