I have a rather old Galaxy 3 phone on Virgin Mobile, I would like to upgrade to a Galaxy 6 they are doing with a "free tablet" but I want to keep my number, if I just put my old sim card into the new phone would this keep my number?
If you remain with VM then it should go smoothly. It is not in their interest to make changing your handset, or whatever, difficult, as then you might go to a different provider.