1<table>
2 <tr>
3 <th rowspan="2" id="h">Homework</th>
4 <th colspan="3" id="e">Exams</th>
5 <th colspan="3" id="p">Projects</th>
6 </tr>
7 <tr>
8 <th id="e1" headers="e">1</th>
9 <th id="e2" headers="e">2</th>
10 <th id="ef" headers="e">Final</th>
11 <th id="p1" headers="p">1</th>
12 <th id="p2" headers="p">2</th>
13 <th id="pf" headers="p">Final</th>
14 </tr>
15 <tr>
16 <td headers="h">15%</td>
17 <td headers="e e1">15%</td>
18 <td headers="e e2">15%</td>
19 <td headers="e ef">20%</td>
20 <td headers="p p1">10%</td>
21 <td headers="p p2">10%</td>
22 <td headers="p pf">15%</td>
23 </tr>
24 </table>