C# Question about Variables

Question

In the 2nd class about C#, it says that "It is called variable because the information stored in that location can be changed when the program is running. "

What does this means and how does it works in practice?

I mean, when I think about variables, I think about the math ones. So, in those questions about "finding the X", the X is a variable, cause we don't know it's value and can be anyone. But, at the end of the question, we perhaps that "X = 4", so it has a value.

When I read this part, I understood that a variable can mean 4 at a time, but it can change to 5 at another time. How does this work?

Answer 1

A variabele is a box.
You can put flowers in the box. Get them out of the box and put books in the box.

string box;
box = "flowers";
Now the box contains flowers
box = "books";
Now the box contains books

In Math it is almost the same. In one sum x can be 5, in another sum x= 10.
A statement is a sum
A Math chapter is a program

Answer 2

It is true what they say that the information held by a certain variable can change, and it can happen many times during the lifetime of the program (while it is running). About how it works is a bit hard to explain, because it is contextual. But for the sake of simplicity let's just take an integer for an example.

Declare integer named "cost" and give it a value of integer 5;

int cost = 5;

Then we change information stored in "cost" by giving it another value;

cost = 10;

By now "cost" is no longer keeping a value of 5 in memory, it is now keeping a value of 10.

I hope this explains a little about it, feel free to ask further if necessary, I will try to help, as I can.