I have to quickly share a conversation Charles and I had the other day, because I found it quite funny:
Charles: What's your 1040?
Charles: Yeah, it means your position, like- where are you?
Me: I'm pretty sure its 20...
Charles: Hmm... really? Why would I think its 1040 then?
Me: I don't know, maybe you are thinking of 10-4, like on a walkie talkie, or isn't there a 1040 tax form?
Charles: Possibly... ok, whats your 1020?
Me: No, I think its just, "What's your 20?" (after googling...) Yeah, see, it says so here on urbandictionary.com
Charles: Yeah... I think you're right. What's your 20?