The Vietnamese team has won numerous medals at the 56th International Mathematical Olympiad, ranking 5th among 104 participating countries and territories.
The six-member team claimed two gold medals, three silvers and one bronze at the 2015 contest, held in Chiang Mai, Thailand from July 4 to 16.
The golds went to 11th grader Vu Xuan Trung, from the northern province of Thai Binh, and 12th grader Nguyen The Hoan, from Hanoi.
The other 12th graders on the team, Hoang Anh Tai, from the central province of Nghe An; Nguyen Tuan Hai Dang, from Hanoi; and Nguyen Huy Hoang, from Ho Chi Minh City, bagged the silvers, and Nguyen Thi Viet Ha, from the central province of Ha Tinh, earned the bronze.
Held annually in a different country each year, the International Mathematical Olympiad (IMO) is the world championship mathematics competition for high school students.
The first IMO was held in 1959 in Romania, with seven participating countries. Nowadays, there are over 100 competing countries and territories.
Earlier, Vietnamese high school students also won big at the 2015 International Physics Olympiad held in India from July 5 to 12.
All five Vietnamese contestants collected medals, including three golds and two silvers.
Twelfth grader Vu Thanh Trung Nam, from Hanoi; 12th grader Nguyen Cong Thanh, from the northern province of Hai Phong; and 11th grader Dinh Thi Huong Thao, from the northern province of Nam Dinh, won golds.
Thao also received a special prize for the female contestants with the highest achievements.
The two silvers were awarded to 12th grader Nguyen Ngoc Khanh, from Nghe An; and 11th grader Nguyen Quang Nam, from the capital.
Last year, the Vietnamese team won three golds and two silvers at the competition.