As its important to know how GPA is calculated please give the steps how its calculated?

As you want to know how gpa is calculated here I show you steps To calculate your science & math GPA, use the following steps:
1. List each course you took or plan on taking and how many credits it is worth.
2. For each course, list the earned or expected grade.
3. Multiply the number of credits by the grade to get the “Grade Points” for each course.
4. Add the Grade Points for each course together to get Total Grade Points.
5. Divide the Total Grade Points by the total number of Credit Hours attempted. Credit hours = the total number of credits you earned and attempted. (Note that you do not earn credits for courses with a grade of 0.0 at MSU)

How to Calculate GPA