Bojana
Each field should only contain 1 value.
NEVER put multiple values in a single field.  That will cause problems in the future.

Example:  Building XYZ has 3 floors with different departments on each floor - retail store, accounting and business office.

Your table would look like this:
Building name:  XYZ
Floor: 1
Department: Retail Store

So the second record would look like:
Building name:  XYZ
Floor: 2
Department: Accounting

and
Building name:  XYZ
Floor: 3
Department: Business Office

This way if you are searching for the Accounting floor you can tell right away it is floor 2 in building XYZ.
Does that help?  Watch the Expert 2 videos again.  it will come to you.

What Scott said is absolutely correct. Also check these out: Relationships Tip, Relationships Seminar

Thanks for the answers, I will watch again and also think how to implement your suggestion on my problem. I want to make DB for real estate agent and try to see is there match between "Home for sale" and "Wanted home". Wanted home for buyers usually is not explicitly defined, they are looking for apartment between 1 and 5 floor, with one or two bathrooms etc. Maybe I can make separate fields, for each of this attributes- FloorMin and FloorMax, BathroomsMin, BathroomsMax. What do you think?

There's a lot of paths to the same ending. Many ways you could do this depending on how you want to run things.

You could do your solution
You could do just floors and only get the exact floors, or program in a + or - 1 floor to pitch ideas that are close, or you could set up a ton of filters that you could turn off/on to find certain combinations that you setup
You could just word the field values like a SQL statement =2, >4, BETWEEN 2 and 4 etc. and run the search off the fields values
I'm sure there's many more I can't think of right now

Lots of options here. Most things have multiple ways to achieve the same goal, you'll learn more and more ways to get to the end the deeper into the classes you go.

Long Story short, there's a lot of right answers, your idea can work, try it out. As long as it works how you want it to, mission successful :).

Yep. Adam has it. Use a query with BETWEEN.