examples/angular/add_numbers_controller.html
<script src="angular.min.js"></script>
<script src="add_numbers_controller.js"></script>
<div ng-app="AddNumbersApp">
    <div ng-controller="AddNumbersController">
        <input ng-model="a" ng-keyup="AddNumbers()">
        <input ng-model="b" ng-keyup="AddNumbers()">
        <h1>{{ sum }}</h1>
    </div>
</div>
examples/angular/add_numbers_controller.js
angular.module('AddNumbersApp', [])
    .controller('AddNumbersController', ['$scope', function($scope) {
        $scope.AddNumbers = function() {
            var a = Number($scope.a || 0);
            var b = Number($scope.b || 0);
            $scope.sum = a+b;
        }
}]);