The top number is the class average of the course work (assignments/quizzes/tests) of my calculus class. The bottom number is the class average of the final exam.
As a teacher, besides ensuring that my students are receiving the best instruction I can provide, the thing I worry about most is whether I am assessing their knowledge properly. It is quite reassuring when these two marks are within 5%. It is extremely reassuring when they are within 0.1% of each other.