The subject became “stupid shit teachers say that is not applicable in the real world” and in that context the subject never changed. They were probably told “you won’t have a calculator in your pocket all the time” as well as “don’t using the internet(google and Wikipedia) as sources” which was very common to be told around the time when they would have been in school. I’m not attacking you I just think you misunderstood as everyone is possible of doing.