factory.js

var app = angular.module('app',[]);

app.factory('MathFactory',function(){
	var factory = {};
  factory.add = function(a,b){
  	return a + b;
  }
  
  factory.subtraction = function(a,b){
  	return a - b;
  }
  
  factory.multiply = function(a,b){
  	return a * b;
  }
  
  return factory;
  
})