how do parameters work in methods? c#

Question

i don’t understand why when you call a method, the parameter is different from the one that you put in first.
(sorry for my bad English, English is not my first language) thank you!

Answer 1

//our method.
mySum(int i, int j){doSomthing;}

//we call and pass arguments.
mySum(10,20);

//arguments passed to the methods parameters.
mySum(int i holds 10, int j holds 20){doSomthing;}

Answer 2

Can you give an example?

Answer 3

sure.
like having this method
static int[] TotalizaMediciones(int[] arregloMediciones)

and then calling it like this
int[] totalesRango = TotalizaMediciones(mediciones);

why do i use "mediciones" instead of "arregloMediciones" when i'm calling the method?