as far as i remember, during initial setup, Whatsapp will derive the number from the system. i.e. the SIM on the phone. (however it is a data-based service, and if you pull the sim, that active whatssapp account will still work)

GV is a virtual number on an application layer, and thus Whatsapp cannot recognize it. to my knowledge.

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however, BECAUSE gv is a virtual number, it will stay fixed no matter where you are, and what sim card you have. It goes through data. If you called or texted my GV number, it will ring wherever i have it set up (on my phone, on my computer, etc). the carrier is inconsequential.