Untitled

<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>

<body>
    <h2 id="title">Calc</h2>
    <input id="firstNum" type="number" placeholder="Enter first number">
    <select id="selectOperator">
        <option value="+">+</option>
        <option value="-">-</option>
        <option value="/">/</option>
        <option value="*">*</option>
    </select>
    <input id="secondNum" type="number" placeholder="Enter second number">
    <button id="doCalc">=</button>
    <span id="resultNum"></span>

    <script src="script.js"></script>
</body>

</html>