The names assigned to the arguments and variables of a function follow the naming conventions of standard variables. The last line of the function returns the calculated Answer to whichever event handler called the function. The return statement must be there or the function would simply perform the calculation and then do nothing. Normally, you want to get something back from a function. The alert command in the function then displays this value in an Alert box.
Nothing is returned to the calling statement.
Well, let's pass them some numbers and see what happens. The scripts of the event handlers in all the buttons are similar. In the current case, parameters A and B, containing the values 5 and 5, are passed. What you need to remember is that the parameters passed by the calling statement are associated with the argument names in the receiving function. The names of the parameters and arguments are, in fact, irrelevant to the working of the function.