# 19.5. Exercises: Objects and Classes, Part 2¶

Work on these exercises in your csharp-web-dev-lsn3and4classes. project. Be sure to checkout the `lsn4-exercises-start` branch. You will update your `Student.cs` file by implementing the `AddGrade` and `GetGradeLevel` methods that were sketched out in the Instance Methods section.

## 19.5.1. The `GetGradeLevel` Method¶

This method returns the student’s level based on the number of credits they have earned: Freshman (0-29 credits), Sophomore (30-59 credits), Junior (60-89 credits), or Senior (90+ credits).

## 19.5.2. The `AddGrade` Method¶

This method accepts two parameters—a number of course credits and a numerical grade (0.0-4.0). With this data, you need to update the student’s GPA.

### 19.5.2.1. GPA Information¶

GPA is computed via the formula:

gpa = (total quality score) / (total number of credits)

1. The quality score for a class is found by multiplying the letter grade score (0.0-4.0) by the number of credits.

2. The total quality score is the sum of the quality scores for all classes.

For example, if a student received an “A” (worth 4 points) in a 3-credit course and a “B” (worth 3 points) in a 4-credit course, their total quality score would be: 4.0 * 3 + 3.0 * 4 = 24. Their GPA would then be 24 / 7 = 3.43.

### 19.5.2.2. Determine the New GPA¶

To update the student’s GPA:

1. Calculate their current total quality score by using the formula `gpa * numberOfCredits`.

2. Use the new course grade and course credits to update their total quality score.

3. Update the student’s total `numberOfCredits`.

4. Compute their new GPA.

## 19.5.3. `ToString` and `Equals`¶

1. Add custom `Equals()` and `ToString()` methods to the `Student` class.

2. Add custom `Equals()` and `ToString()` methods to the `Course` class which you started in the exercises for the previous chapter.