index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="calculator.css">
    <link href="https://fonts.googleapis.com/css2?family=Commissioner:wght@600&display=swap" rel="stylesheet">
    <link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
    <script defer src="calculator.js"></script>
    <title>Calculator</title>
</head>
<body class>
    <div id="page">
    <table id="calculator">
        <tr>
            <td id="screen" colspan="4">0</td>
        </tr>
        <tr>
            <th class="icon"><i class="material-icons">clear</i></th>
            <th>/</th>
            <th>*</th>
            <th class="icon"><i class="material-icons">backspace</i></th>
        </tr>
        <tr>
            <th>7</th>
            <th>8</th>
            <th>9</th>
            <th>-</th>
        </tr>
        <tr>
            <th>4</th>
            <th>5</th>
            <th>6</th>
            <th>+</th>
        </tr>
        <tr>
            <th>1</th>
            <th>2</th>
            <th>3</th>
            <th rowspan="2">=</th>
        </tr>
        <tr>
            <th colspan="2">0</th>
            <th>.</th>
        </tr>
    </table>
    </div>
</body>
</html>