Greg is an A-student, and is a freshman in highschool. His teacher thinks he is having trouble with "base ten" division. Since Greg is smart, and is a freshman, his teacher should know that Greg can do elementary math.
Linda, who is reportedly from Seattle seems to not be able to pronounce the city she lived in right, saying "See at tail". Wouldn't someone who lived there the majority of their lives be able to say it properly?
The episodes name - "The Undergraduate", is taken from Dustin Hoffman's movie "The Graduate", which has a similar story.