Edit in JSFiddle

Result
HTML
JavaScript
CSS

<body ng-app="myApp" ng-controller="toggleDIV">
    
<input type="button" ng-click="toggleDiv()" value="Toggle Div" />       
<div class="fadein fadeout" ng-show="divToShowHide">Hello</div> 
    
</body>

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

app.controller("toggleDIV", function($scope){

    $scope.divToShowHide = true;
    
    $scope.toggleDiv = function(){        
        $scope.divToShowHide = $scope.divToShowHide === true ? false: true;
    };
    
});

.fadein,
.fadeout {
  background: #2e7cb8; padding: 10px; color: #fff;
  -webkit-transition: all 0.5s linear;  
  transition: all 0.5s linear;    
}

.fadein.ng-hide-remove,
.fadeout.ng-hide-add.ng-hide-add-active {
  opacity: 0;
  display: block !important;
}

.fadeout.ng-hide-add,
.fadein.ng-hide-remove.ng-hide-remove-active {
  opacity: 1;
  display: block !important;
}