wt iz grading system???

To know the grading system, go through the following link.

How grades are better than marks:

Grades create a certain slab under which a student can be categorised.
Impartiality and equality are maintained among students who fall under same category.
Teachers can justify their marking in grading system. In case of marks, teachers cannot explain the difference between 80% and 81% because it is influenced by the teacher's perception especially in case of theoretical subjects.