The US education is based on academic grading and credit system rather than the numeric grading system which is otherwise widely used. The five letter grade system most commonly used up to the mid twentieth century was A, B, C, D and F, where A denoted the highest possible grade and F stood for failure. In the mid twentieth century, many part of the United States replaced the Grade F which was for 'Failure' and started to use E instead of it when the marks went down below the minimum requirement to pass. Another grading system which was also used the early twentieth century was E S N U system where each letter denotes the performance of the student, where E was for Excellent performance, S was for satisfactory, N for Needs Improvement and U for Unsatisfactory.

#### The grading and numerical point

The five grades are given to the students based on the marks or the percentage of marks they obtain in a given set of paper. The grades are also correlated to a five point scale of 0 to 4 where 0 is the least possible grade which also signifies an E or failure and the 4 point is the best grade which also signifies maximum mark or grade A. besides four point grades, nine point and eleven point grades are also followed by some institutions.

#### The grading and its variation

The maximum grade which is 4 corresponds to the grade A is also calculated as the excellent grade. The next point, 3 corresponds to grade B, which means good performance. The point 2 is equal to grade C, which is for average performance. And the last success numerical point 1 corresponds to grade D which means satisfactory. The least grade given to any student is point 0 which means failure or grade E.

Besides the perfect A, B, C, D and E there are chromatic variants of the grade given to the students which are denoted by a '+' or a '-', where the B+ grade denotes a point of 3.3 and B – denotes 2.7 points and a simple B means 3 points. This was applicable to all the grades, but the grade A+ is not usually used in the united States as an 'A' or point 4 is considered as the maximum grade to be obtained by anyone and any point higher than 4 is not there on the scale. Similarly D- is also omitted on the grading scale as anything less than D is considered a failure.

Some institutions follows a single midpoint denoting the + and – which means B+ and A- corresponds to a point of 3.5. To eliminate this confusion while having a single midpoint of what grade is to be given when the point is 3.5 or 2.5, institutions like the University of Wisconsin introduced the combined Grade AB instead of the A- and the B+, similarly, BC was introduced instead of B- and C+.

#### The percentage of marks and the grade awarded

Grade A corresponds to 90 to 100% marks
Grade B corresponds to 80 to 89% marks
Grade C corresponds to 70 to 79 % marks
Grade D corresponds to 60 to 69% of marks and
Grade E corresponds to 59% and below
Besides the five point scale, there is also a ten point scale as the one used by the Rackham School of Graduate studies which denotes each grade on different point scale.
A+ corresponds to point 9, A to point 8 and A- to point 7
B+ corresponds to point 6, B to point 6 or 5 and B- to point 4
C+ corresponds to point 3, C to point 2 and C- to point 1
There is no grade D and the last grade E corresponds to a point of 0 or failure.

#### The GPA Score

High schools and University gives the GPA scoring to the students based on the overall performance and the average grades obtained during the time at the school or college.  The GPA are calculated usually on a four point scale and the maximum GPA of 4 equals to 100 percent on a 100 point scale. The undergraduates are to complete their course with an average GPA of 2 or Grade C and the Graduates on an average grade of B or GPA 2 to go for further specialization though the passing grades are D and C respectively. Those of who gets an E grade or fails are required to redo the course.