When summer ends, Dill returns to Mississippi. Scout starts her first year of school. She hates it from the first day. Her teacher, a newcomer to the town named Miss Caroline, actually criticizes Scout for knowing how to read.
Mockingbird depicts standardized education as rigid to the point of absurdity. Miss Caroline's criticism of Scout's reading ability is a case in point.
Just before lunch, Miss Caroline discovers that one boy, Walter Cunningham, has brought no food and does not go home to eat. Miss Caroline offers to lend Walter a quarter, but he refuses. Scout tries to explain that the Cunningham's are so poor they couldn't pay Miss Caroline back, and that Miss Caroline is "shaming" Walter by trying to force the quarter on him. Miss Caroline gets annoyed and "whips" Scout by tapping her palm with a ruler.
This episode establishes that there are economic differences between families in Maycomb. At this point, Scout simply accepts such differences as the way things are; she feels neither sympathy nor prejudice toward Walter. Miss Caroline's "whipping" of Scout for explaining about Walter shows how out of touch Miss Caroline is.