An early mentor of mine once said to me: “Kid, you don’t know shit. And that’s okay — as long as you know what you don’t know.”
In life one thing is a given: There are always many more things you don’t know, than those you do. Be it understanding a particular algorithm or pattern, how to manage your team for maximum effectiveness, how to read a complex P&L statement or a legal contract.
This is all fine — as long as you don’t fall into the trap of believing that you ought to know these things and start to bullshit yourself and those around you. Or worse (and much more dangerous): Believing that you actually do know these things in the first place.
Luckily there is little (if anything) which you can’t look up, ask for advice, outsource or learn these days. Thus you do well to know what you know, know what you don’t know — and simply ask.
There is no shame in asking and/or admitting that you don’t know.
The best entrepreneurs I know will tell you, when confronted with a question they don’t know the answer for, that they will find out and come back to you.
P.S. This advice is particularly important for pitches — you are far better off admitting that you don’t have the answer for a particular question than BS’ing around (which every smart investor can smell a thousand miles against the wind).