Indonesian has a long historical journey as a means of communication as well as a symbol of national identity. This study discusses the dynamics of the development and position of Indonesian using the library research method. Library research used in this study can be in the form of books, articles and journals, which are based on various historical references and academic studies. Originating from the Malay language which has long functioned as a lingua franca in the Nusantara region, Indonesian was then inaugurated as a unifying language through the Youth Pledge in 1928 and was confirmed in the 1945 Constitution as the state language. The discussion also covers the important role of Indonesian in various sectors, such as the world of education, government bureaucracy, mass media, and the realm of technology. Based on the results of the literature review, it can be concluded that Indonesian plays a role not only as a means of communication, but also as an important element in the formation of national identity and the integration of a pluralistic society. This study emphasizes that the existence and function of Indonesian continue to develop in line with social change and progress.

Ethnomathematics is one of the approaches that integrates local wisdom with mathematics learning. This study aims to develop PBL-based LKPD with ethnomathematics nuances at the Maimun Palace. This research method is research and development (Research and Development). The development model used as the basis for this study is the ADDIE development model (Analysis, Design, Development, Implementation and Evaluation). The results of the study showed that the LKPD developed was included in the valid category, for the average overall result of the LKPD validation assessment from the three validators was 4.35. In the implementation, the response of students to the LKPD with an average score of 4.48 was categorized as very good and met the practicality of the LKPD, so it did not need to be revised again. The PBL-based LKPD with ethnomathematics nuances produced, along with its supporting instruments, have met the criteria of validity, practicality, and effectiveness.