Seven of the 666 contestants from 117 countries and territories reached full marks, according to the official IMO results, which show Deng taking 7 out of 7 on all six problems. China finished first with 232 points, 25 clear of the U.S., and all six of its contestants won gold, Shanghai Daily reported.
The U.S. team placed second with four golds, and its own perfect scores went to Alexander Wang and Liam Reddy, according to the Mathematical Association of America, which organized the American team.
Achieving perfect scores at separate olympiads like Dang is rare in China. Jimu News reported in 2024 that Shi Haojia had become only the fourth Chinese contestant to manage it, after Luo Wei, Fu Yunhao and Wei Dongyi. Wei, who scored 42 in both 2008 and 2009, is now an assistant professor at Peking University and a minor celebrity in China.
But Dang has experienced not only winner glory in his student life. He did not do so well in languages in secondary school, and used to cry over it.
At the opening ceremony of Huayu Private Middle School in Shanghai on Aug. 31, 2025 after winning the IMO gold that year, Deng told students about scoring 89 out of 100 on a seventh-grade English exam, exactly the class average, The Paper reported. The class monitor scored 99, and Deng heard that the teacher had deducted a point deliberately to stop the boy getting arrogant.
