Practice exercises CHAPTER 6 303
<h1>Contoso Ltd.</h1>
<h2>Your success equals our success</h2>
</hgroup>
</header>
<nav>
<a href="default.html">Home</a>
</nav>
<div role="main">
<div id="calculator">
<table>
<tr>
<td colspan="4">
<input id="txtResult" type="text"
readonly="readonly" />
</td>
</tr>
<tr>
<td colspan="4">
<input id="txtInput" type="text" />
</td>
</tr>
<tr>
<td></td>
<td></td>
<td>
<button id="btnClearEntry">CE</button>
</td>
<td>
<button id="btnClear">C</button>
</td>
</tr>
<tr>
<td>
<button id="btnNumber7">7</button></td>
<td>
<button id="btnNumber8">8</button></td>
<td>
<button id="btnNumber9">9</button></td>
<td>
<button id="btnPlus">+</button>
</td>
</tr>
<tr>
<td>
<button id="btnNumber4">4</button>
</td>
<td>
<button id="btnNumber5">5</button>
</td>
<td>
<button id="btnNumber6">6</button>
</td>
<td>
<button id="btnMinus">-</button>
</td>