<!DOCTYPE html>
<html>
<body>
<h2>Common JavaScript Mistakes</h2>
<p>Adding a number as a number produces a different result from adding a number as a string:</p>
<p id="demo"></p>
<script>
let x = 10;
let y = "5";
let z = x + y;
document.getElementById("demo").innerHTML = z;
</script>
</body>
</html>
