fn_with_args.js

// the reason we have functions is to avoid 
// repeating code
function sum(arg1, arg2) {
    var number1 = arg1;
    var number2 = arg2;

    var sumOfNumbers = number1 + number2;
    console.log(sumOfNumbers);
}

sum(1, 2);
sum(100, 200);
sum(1000, 2000);

// In the above statement, we are calling the function SOME_NAME() 
// and it will print the sum of the numbers.

// calling the function means that we are asking the function 
// to execute the code inside it.