<!DOCTYPE html>
<html>
<head>
<title>Document</title>
</head>
<body>
<form oninput="x.value=parseInt(a.value)+parseInt(b.value)">
<input type="range" id="a" value="50">
+<input type="number" id="b" value="55">
=<output name="x" for="a b"></output>
</form>
</body>
</html>
