Nana Maru San Batsu

Bunzou High School is welcoming its new first-year students. One of them, Koshiyama Shiki, is chosen to participate against his will in an impromptu fast-buzzing quiz meet by the president of the Quiz Bowl Circle. As a quiet boy who loves reading and doesn't want to stand out, Shiki is overwhelmed, but his classmate, Fukami Mari, is able to hit the buzzer and answer questions before the full question is given. As he watches her, Shiki realizes that there's a point in each question where the answer becomes certain. (Source: Crunchyroll)