AngularJs expression is used to bind the data in HTML and It is used to write inside the {{ }}. It is the alternative of ng-bind directive. It will display the output where expression has been written.
Sample Code for integer data
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8" />
<script src="../Scripts/angular.min.js"></script>
</head>
<body>
<div ng-app="">
Addition of 2 Num : {{ 10+20 }}
</div>
</body>
</html>
Note: Here we have injected ng-app so it is doing addition. If we will remove then it will not work.
Sample code for Multiplication of 2 Num
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8" />
<script src="../Scripts/angular.min.js"></script>
</head>
<body>
<div ng-app="" ng-init="Num1=10; Num2=20">
Multiplication of 2 Num : {{ Num1 * Num2 }}
</div>
</body>
</html>
Note: Here ng-init is used to initialize the data.
For String Concatenation Example
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8" />
<script src="../Scripts/angular.min.js"></script>
</head>
<body>
<div ng-app="" ng-init="FirstName='Chandradev'; LastName='Prasad'">
String Concatenation : {{ FirstName + " " + LastName }}
</div>
</body>
</html>
Note : Here same things can do using ng-bind like this
<div ng-app="" ng-init="FirstName='Chandradev';LastName='Prasad'"> String Concatenation : <span ng-bind=" FirstName + ' ' + LastName" ></span> </div>
Angular Object Example
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8" />
<script src="../Scripts/angular.min.js"></script>
</head>
<body>
<div ng-app="" ng-init= "Emp={FirstName :'Chandradev', LastName:'Prasad'}">
Emp Name : {{ Emp.LastName }}
</div>
</body>
</html>
Array example in Angular
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8" />
<script src="../Scripts/angular.min.js"></script>
</head>
<body>
<div ng-app="" ng-init= "Numbers=[1,4,6,8,10]">
4th Num: {{ Numbers[3]}}
</div>
</body>
</html>
Chandradev's Blog 