How do ADN programs calculate GPA

[Javimonster]

Hi everyone, 

 I have a few questions of how ADN programs general ED GPA is calculated. Are only the core classes needed as pre-req taken into account or is it for all the classes I've take in the past years.

 My GPA is kinda low due to about 20 credits I've taken in the past. Im currently 18 credits in and I've managed to get all A's. Im wondering where my GPA will be once I apply to the ADN programs in my area. (Chaffey, Rcc, Mt.Sac) Thank you!