Show unselected items from a multi select field

Hello. I have the same question as here - Display multi-select items not selected
But it seems as though there is no answer in that thread. Does anybody know the solution to this? What formula can show only unselected in some field items?

Yeah, questions more cumbersome to ask then answer do be like that.

But to indulge you: there are plenty of ways to accomplish your stated goal. Airtable formulae are one of them. But a single rollup would be more elegant, in this instance (it’s just a fancy formula, anyway).

Either way, Airtable’s product docs are probably the best in biz - don’t be afraid to peruse them.

Im intrigued by what usecase you might need this in.
how many multi select options are there? if theres only a few ill try to write something for you and explain it but i cant make any promises.

Multi select options are not many, not more than 5.
The usecase is such:
A learner chooses the time for his classes and a teacher. So for example Teacher 1 has 2 learners on Monday at 6pm and 7pm, but he also has free time at 8pm. I want that in the table where all teachers are listed there would be a field with teacher’s free time.
In my case, time variants are multi select options. So I have such fields in my table:
Field 1 - all teacher’s time variants.
Field 2 - booked teacher’s time variants.
Field 3 - free teacher’s time variants.
So I need Field 3 automatically filled according to Field 1 and Field 2
Thanks in advance.

im not following. can i see a screenshot?

Sure. That’s it.

So I need field Free Monday time to be auto calculated. And in my table for Teacher 1 Free Monday time would be 19:00 and 20:00 (they should be in the form of multi select options).

ooooooooooohhhhhh ok that makes more sense. i will work on a solution and come back.