A high-achieving math student from Ho Thi Ky High School in Ca Mau has faced serious repercussions after his perfect score of 10 in the national high school graduation exam was nullified due to the use of a mobile phone during the test.

The situation arose from social media allegations that the student was seen using his phone during the Vietnamese Literature and Math exams on June 11. While several other students noticed the violation, they did not report it to the exam supervisors. However, the issue was eventually brought to the school's attention, leading to the student's phone being confiscated the following day.

On July 1, when exam results were published, it was revealed that the student scored 10 in Math, 6 in Literature, and lower scores in Physics and Chemistry. Upon investigation, Nguyen Van Nguyen, the Director of the Ca Mau Department of Education and Training, confirmed that the student admitted to using his phone during the Math exam.

Despite the allegations circulating online, the school's administration reported no unusual activities during the exam. The student's academic records for grades 10, 11, and 12 showed impressive scores of 8.5, 9.3, and 9 in Math, respectively, and he was a member of the school's provincial math competition team.

The Ca Mau Department of Education and Training has stated that they will report the incident to the provincial People's Committee for further action against the student and the exam supervisors involved. According to the exam regulations, the use of mobile phones is strictly prohibited, and any violations by 12th-grade students result in the nullification of their exam results, effectively marking them as having failed to graduate.

The national high school graduation exam is scheduled for June 11-12, 2026, with the organization of the exam being delegated to provincial and municipal authorities, including supervision and grading responsibilities.