Recent advances in large language models (LLMs) have demonstrated strong mathematical reasoning abilities, even in visual contexts, with some models surpassing human performance on existing benchmarks. However, these benchmarks lack structured age categorization, clearly defined skill requirements, and—crucially—were not designed to assess human performance in international competitions. To address these limitations, we introduce MathGames, a new benchmark of 2,183 high-quality mathematical problems (both text-only and multimodal) in an open-ended format, sourced from an international mathematical games championships. Spanning seven age groups and a skill-based taxonomy, MathGames enables a structured evaluation of LLMs’ mathematical and logical reasoning abilities. Our experiments reveal a substantial gap between state-of-the-art LLMs and human participants—even 11-year-olds consistently outperform some of the strongest models—highlighting the need for advancements. Further, our detailed error analysis offers valuable insights to guide future research. The data is publicly available at https://disi-unibo-nlp.github.io/math-games.