Competition time of the National Mathematical Modeling Competition for College Students (National Competition): it is held in September every year (usually 72 hours from Friday to next Monday on a weekend in the first half of the year), and the competition is open to college students all over the country, regardless of majors (but the competition is divided into undergraduate group and specialist group, all college students can participate in the undergraduate group competition, and junior college students (including vocational and junior college students) can participate in the specialist group competition).