Return value to method in class

[luz]

Hi...i'm still new at this js oo..what i would to do is return value from a one class method to the other..as you all can see below i have 2 simple class which is MyMath and MathResult..the problem is how can i return the value of this.DoMath() which is this.total in MyMath to this.ShowMathResult in MathResult..thanking you all in advance for reviewing my post

function MyMath(){
	this.StartMath = function(a,b,c){
		this.a = a;
		this.b = b;
		this.c = c;
		this.DoMath();	
	};
	this.DoMath() = function(){
		this.total = this.a +this. b - this.c; 
		return this.total;
	};
	
}
function MathResult(){
	this.ShowMathResult = function(){
		 alert(this.total);
	}
}