if you don't know your worth, you're entering the job market in a position of relative weakness, and no amount of third grade negotiation tricks like "not telling the first number" will make up for it.

what do you think, that by witholding that number, they'll start negotiating from the upper half of their budget range? that's wishful thinking, at best. no, they will offer whatever they think they'll get away with, and it will pin your salary discussion to a number they decided

I have no idea how people think that that is a good outcome.