According to the text in Chapters 4 and 5 of the book, what action by Penny's mother leads Penny to believe that her mother is now in a happier mood than Penny has ever known her to be?

According to the text in Chapters 4 and 5 of the book, Penny is led to believe that her mother is now in a happier mood than Penny has ever known her to be, because she has noticed that her mother has been smiling a lot more lately.