<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <link rel="stylesheet" href="style.css">
    <title>Document</title>
</head>
<body>
    <div id="canvas">
        <div id="primary-number">7</div>
        <div id="add">+</div>
        <div id="secondary-number">10</div>
        <div id="equal">=</div>
        <div>
            <input type="