There is a relationship between the picture frame and the dotted line on the math answer sheet of the college entrance examination. The function of the picture box is to specify the answer area, and the dotted line is for the convenience of filling in the answer. On the answer sheet, each small question has a rectangular box, which is the answer area, and the dotted line divides the answer into several small squares. Candidates need to fill in their answers in each small box to prevent the answers from crossing the line. At the same time, candidates should also be careful not to cross the dotted line when filling in the form, otherwise it may affect the machine-readable performance.