UA tracking code

Is the UA tracking code number the same in the network settings as the main site? I had deactivated the analytics while in production, now that I have reactivated it, I see that the network setting does not have a UA tracking code but the main site does. Should I just copy the main site number into the network setting? The main site & subsites settings page have a link to Google Analytics to get UA but the network setting page doesn't have the Google Analytic link but just the settings form. I just want to make sure whether I am supposed to have two separate numbers (since I am actually one account) or just one.