I need to do two `$http.get` call and I need to send returned response data to my service for doing further calculation.

I want to do something like below:

```
function productCalculationCtrl($scope, $http, MyService){
    $scope.calculate = function(query){

            $http.get('FIRSTRESTURL', {cache: false}).success(function(data){
                $scope.product_list_1 = data;
            });

            $http.get('SECONDRESTURL', {'cache': false}).success(function(data){
                $scope.product_list_2 = data;
            });
            $scope.results = MyService.doCalculation($scope.product_list_1, $scope.product_list_2);
        }
    }

```

In my markup I am calling it like 

```
<button class="btn" ng-click="calculate(query)">Calculate</button>

```

As `$http.get` is asynchronous, I am not getting the data when passing in `doCalculation` method.

Any idea how can I implement multiple `$http.get` request and work like above implementation to pass both the response data into service?