Number function converts object value to number
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
</head>
<body>
<script id="javascript">
var value=prompt("what is your age?","");
alert(value+7);
var num= Number(value);
alert(num+7);
</script>
</body>
</html>
