Why does it say “approximately” next to the location?
The location is worked out from the IP address, which is often a nearby city rather than where the device actually is. Use it as a rough signal — the device, the browser and the two-digit number are the reliable parts.
From the guide Approving Sign-ins on Your Phone.
The two-digit number is the whole point
A prompt with nothing but an “Approve” button is a prompt people eventually tap to make the buzzing stop — which is exactly what somebody who has stolen your password is counting on. The number breaks that: if you are not sitting in front of a sign-in screen showing that number, the request is not yours. Never approve a prompt whose number you cannot see on a screen in front of you, and never read the number out to anybody who phones you.
Nobody from Seayora will ever call and ask you to approve a sign-in prompt or read a number from it.
Read the whole guide: Approving Sign-ins on Your Phone