Intuiting a phone extension

2001
I was calling a friend of mine at work and for the first time. A recording came on that said “If you know your party’s extension enter it now.” I had no idea what it was so I just centered myself and said, "ok, I need an extension" and 3 numbers came to me so I dialed them. My friend answered the phone and when he realized it was me he said “How did you find me?” I said "You won’t believe me. Why do you ask?" He said he just stepped into this conference room to check something and the phone rang so he answered it. The fact that I got three numbers (since extensions can range from 1 to 5 digits long) and they were the exact three numbers of the room he had just stepped into was pretty cool.