Selected Answer
Hi there! It seems like you want to use a VLOOKUP function or INDEX/MATCH lookup in another cell to get the data you want.
Here is an example:
=VLOOKUP(A1,D1:E3,2,FALSE)
A1 would be the cell with the drop down menu.
D1:E3 would be the table where you have A in D1 and 111 in E1 and B in D2 and 222 in E2, etc.
Update:
Try this for your file:
=VLOOKUP(C1,C7:D9,2,FALSE)
If that doesn't work, please try to explain in more detail what you are doing. Your worksheet is using overly complex ways to do simple things. I didn't offer suggestions to change it because I thought that maybe it is part of a larger file and it has to be like that.