Them: "What's your number"? You: "$350k." Them: "Ok, cool lets move forward." or "That's a lot of money and we can't pay that much. Thanks for meeting with us."
I'm assuming that you've done your homework and know what a reasonable top of the range is. If that's the case, just say what your number is and let them decide if it's too much.
It's very possible for a candidate to be thinking something like "I'm currently making $200K. I think it's possible I could get $300K, but $250K would probably be acceptable, and I might even settle for a lateral move of $200K if I find the position really appeals to me." What should they say? $300K and possibly price themselves out? $200K and possibly lowball themselves?
I was surprised with how much I was able to get away with negotiating my first tech job. It was a little bit of back and forth, a recruiter was involved, and I could just poker face my way into a six-figure job.
If they say 200k are you want to just say 250k and see if you get it.
Like everything it's just quicker and easier if you rip off the band-aid and just do it.