254 CHAPTER 5 More HTML5
<button id="btn6">6</button>
</td>
<td>
<button id="btnMinus">-</button>
</td>
</tr>The next table row will have buttons 1, 2, and 3 and an empty column as follows.
<tr>
<td>
<button id="btn1">1</button>
</td>
<td>
<button id="btn2">2</button>
</td>
<td>
<button id="btn3">3</button>
</td>
<td>
</td>
</tr>
The last table row will have an empty column, the 0 button, and two more empty
columns as follows.
<tr>
<td></td>
<td>
<button id="btn0">0</button>
</td>
<td></td>
<td></td>
</tr>
The following is the completed main <div> element.
<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>