Variables that can be overwritten between users?

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C#

ASP.NET

Hello everyone! I would like to ask you a question that is perhaps a little unusual but which I cannot answer, perhaps because I lack certain bases.

I state that we are talking about ASP.NET web application in C #.

The question is this: if I have a web application that performs calculations using common variables, whether these are static or not, and this application is accessed by multiple users from different locations via a usual URL, eg. www.mysite.com/application.aspx, can it ever happen that a user get the variable V1 modified by another user? Let me explain better: the "application.aspx.cs" class performs the sum of the values entered in two variables, V1 and V2; user 1 populates the variables as follows: V1 = 5 and V2 = 4; in the meantime, a user 2 connected to the same application www.mysite.com/application.aspx from who knows where in the world, is performing the same sum but has entered V1 = 3 and V2 = 7; in short, can it happen that the variables as populated by user 1 are overwritten by user 2?
If this is not possible (as I hope) can you explain to me why?

I hope I have explained clearly.
Thank you.

What I have tried:

I've tried to create different folders, a folder for each user, to prevent this possibility.

Eg.:
www.mysite.com/user1/application.aspx
www.mysite.com/user2/application.aspx
Etc...