Controller escopo correto

HTML

<body ng-app="myApp">
  <div ng-controller="myCtrl">
    
    <button ng-click="count = count + 1">Click Me!</button>
    
    <p>{{ count }}</p>
  
  </div>
</body>

JavaScript

var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
  $scope.count = 0;
});