Nobita’s test scores are specifically mentioned a total of 43 times, and Nobita scores zero points on 26 of those tests, giving him an approximately 60% rate of total failure.
After spending two days reading all 45 volumes of the Doraemon manga, Yanagita discovered that the subject of studying and Nobita’s poor academic skills comes up in a total of 170 chapters.
Additionally, Yanagita notes that in the anime adaptation of the “Test ni Ankipan” chapter of Doraemon, Nobita gets zero points on two consecutive twenty question true-false quizzes.