It might not be obvious to the beginners. There are several implied assumption for mentioning the open problems.

1. This is the problem you have thought about
2. You couldn’t figure out so you are asking audience for help.

As a result, whenever you show the open problem, it is a convention not only knowing the problem is open but

1. what is the current best bound
2. How close are we in proving it
3. What is some difficulties or “proof of failure”