Ladies and Gentlemen, I can be taught!

I just had a woman inform me that the zip code I gave her was incorrect. I told her it was 12345 (not really, obvs) and she said "No, it's 12445". Ummmmmmmmm, do you have the zip code for every address in the Pacific Northwest memorized (and if so why are you calling). She then proceeded to tell me "It can't be 1245, that's not enough numbers. Zip codes have 5 numbers". Well, thanks for telling me. I had no clue. I have never sent or received anything in the mail in my life. Nor do I look up things by zip code every. single. day.