Demo
<iframe height='265' scrolling='no' title='YxQOjK' src='//codepen.io/fastfoodcoding/embed/YxQOjK/?height=265&theme-id=light&default-tab=result&embed-version=2' frameborder='no' allowtransparency='true' allowfullscreen='true' style='width: 100%;'>See the Pen <a href='https://codepen.io/fastfoodcoding/pen/YxQOjK/'>YxQOjK</a> by fastfoodcoding (<a href='https://codepen.io/fastfoodcoding'>@fastfoodcoding</a>) on <a href='https://codepen.io'>CodePen</a>.
</iframe>
Code
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js">
</script>
<script>
$(document).ready(function() {
$("#result").toggleClass("result");
//Addition
$("#add").click(function() {
var a = $("#cal1").val();
var b = $("#cal2").val();
$("#result").html(+a + +b);
});
//Subtraction
$("#sub").click(function() {
var a = $("#cal1").val();
var b = $("#cal2").val();
$("#result").html(+a - +b);
});
//Multiplication
$("#mul").click(function() {
var a = $("#cal1").val();
var b = $("#cal2").val();
$("#result").html(+a * +b);
});
//Division
$("#div").click(function() {
var a = $("#cal1").val();
var b = $("#cal2").val();
$("#result").html(+a / +b);
});
});
</script>
<style>
.result {
font-size: xx-large;
color: blue;
}
</style>
</head>
<body>
<div>
Enter Number :
<input type="text" id="cal1"><br><br> Enter Number :
<input type="text" id="cal2"><br><br>
<button type="button" id="add"> Add </button>
<button type="button" id="sub"> Sub </button>
<button type="button" id="mul"> Mul </button>
<button type="button" id="div"> Div</button><br><br><br> Result is:
<p id="result"></p>
</div>
</body>
</html>