​x
 
<!DOCTYPE html>
<html>
<body>
​
<p id="demo"></p>
​
<script>
var x = [];
document.getElementById("demo").innerHTML =
(5 + null) + "<br>"  +
("5" + null) + "<br>" +
("5" + 2) + "<br>" +
("5" - 2) + "<br>" +
("5" * "2") + "<br>" +
("5" / "2") + "<br>"
</script>
​
</body>
</html>
​