This master's thesis explores the use of large language models (LLMs) for individualised support in secondary school mathematical education. The theoretical part reviews the capabilities and limitations of LLMs, with a focus on their application in educational environments and mathematics-related tasks. Based on the theoretical part, a multiplatform mobile application enabling the generation of mathematical exercises and tutoring dialogue using an LLM was designed and implemented. The application was then deployed in a real classroom setting and evaluated using both quantitative and qualitative methods. Although the quantitative results did not show a statistically significant improvement in students’ academic performance, the qualitative analysis provided insights into how students interacted with the system and communicated with the LLM. The work contributes to the understanding of how students engage with LLM-based educational systems in mathematics education and presents a functional prototype that may serve as a basis for further development.