Noob Help - Actionscript Returns

Question

I am brand new at using actionscript and am having a hard
time understanding what the return..... code/command/function?? is
for. Here is a simple example of script :
var number1:Number = 5;
var number2:Number = 2;
var numberSum:Number;
function addNumbers(pNum1:Number, pNum2:Number):Number {
var sum:Number = pNum1 + pNum2;
return sum;
numberSum = addNumbers(number1, number2);
trace('The sum of number1 and number 2 is: ' + numberSum);
I'm not seeing how the return code is related to the last
part of the script. I understand that it is "returning" the var sum
but where is it going and how is it related to the last bit?

Answer 1

The return is getting set to the variable numberSum. The
following line tells us this: numberSum =
addNumbers(number1,number2);
When you set a variable = a function, the variable is
expecting a return value to come out of that function.
"But why can't you just call the variable sum?" - The
variable sum is local to the function only, and therefore is only
available inside of the function. In order to get its value out of
the function, you need to tell the function to return it to the
caller, which, in this instance, happens to the variable
numberSum.