class and GPA

hey guys most likely will be withdrawing from my math class yea a lil over $250 down the tubes but dont know if i will pass, teacher talked a different language in teaching today the whole time i was like what is she talking about, why am i still here. Anyways every other math class i retook 1 or 2 times, so i might as well get out of this now before it brings down my gpa. I was only taking this class as 1 of 3 to get a degree in something else but i change my mind. Math and science are just not my thing. If i still was with cl the guy from previous entry he would be disappointed, but i’m not so don’t have to deal with him being dissappointed in me. By the way does anybody know how to calculate a grade into current gpa.