template.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <link rel="stylesheet" href="style.css" />
</head>
<body>
    <h1>xin chao the gioi</h1>
    
    <div id="calculator">
        <div class="result">0</div>
        
        <div class="row row1">
            <div class="box clear">C</div>
            <div class="box back">⬅️</div>
            <div class="box">/</div>
        </div>
        <div class="row row2">
            <div class="box">7</div>
            <div class="box">8</div>
            <div class="box">9</div>
            <div class="box opr">x</div>
        </div>
        <div class="row row3">
            <div class="box">4</div>
            <div class="box">5</div>
            <div class="box">6</div>
            <div class="box opr">-</div>
        </div>
        <div class="row row4">
            <div class="box">1</div>
            <div class="box">2</div>
            <div class="box">3</div>
            <div class="box opr">+</div>
        </div>
        
        <div class="row row5">
            <div class="box">0</div>
            <div class="box equal">=</div>
        </div>
    </div>

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