I use md5 checker from the play store. In the app, you load the file to be checked (I do it once the file is in it's final location) and then paste the md5 from where ever you downloaded it from. Then it just tells you if they match or not. Conversely, just long press in astro, root explorer, etc. and click details or properties. That'll show you the md5, and just see if it matches the one listed where you downloaded the file from.