<image>The following math problem is to be translated into English, retaining the  identifier.

The chart below shows the number of male and female students in each grade at Guangming Primary School.

(1) The grade with the most male students is ____ grade, and the grade with the most female students is ____ grade.
(2) The grade with the most students is ____ grade, and the grade with the fewest students is ____ grade.
(3) The number of boys in the third grade exceeds the number of girls by ____.
(4) There are ____ students in Guangming Primary School, including ____ boys and ____ girls.