Here it is with html form:
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8/>
<title>JavaScript program to calculate multiplication and division of two numbers </title>
<style type="text/css">
body {
margin: 30px;
}
</style>
</head>
<body>
<form>
<div>Number:</div>
<div><input type="number" id="num1"/></div>
<div><input type="button" value="Calc Sum" onclick="sumNumbers()"/></div>
<div>Result: <span id="result"></span></div>
</form>
<script>
function sumNumbers() {
let num1 = document.getElementById('num1').value;
let sum = Number(num1) * parseInt("2");
document.getElementById('result').innerHTML = sum;
}
</script>
</body>
</html>