For instance, you have assigned number +44-7485456768 for (source 1), that is the United Kingdom and number +61-7589768 for (source 2) for Australia, and number +1-6264893785 for (source 3) the U.S.
Now, when someone visits your website from Australia; he/she will see +61 7589768 number on the website; whereas someone visiting the website from U.S will see the number assigned to the U.S that is source 3.