How to convert 2 column HTML table to 3 column - html

Question

I'm very new to HTML. I have an HTML document that is built using a 2 column table. I am now needing to set up a row with 3 columns. From the research that I've done, it seems that I can't just add a column to 1 row, rather I need to work with a 3 column table and use colspan in the other rows to make things work. Is that correct?
I've tried adjusting the existing colspans from =2 to =3 and adding a new column to the desired row but to no avail. Can you tell me what is wrong with my approach or how to properly convert the existing 2 column table to a 3 column structure?
<table width="768" border="0" align="center" cellpadding="0" cellspacing="0" style="border:1px solid #000000" >
<tr>
<td colspan="2" width="768" height="160" border="0" style="display:inline" /></td>
</tr>
<tr>
<td colspan="2"></td>
</tr>
<tr>
<td colspan="2"></td>
</tr>
<tr>
<td colspan="2"></td>
</tr>
<tr>
<td colspan="2"></td>
</tr>
<tr>
<td width="256"></td>
<td width="256"></td>
<td width="256"></td>
</tr>
<tr>
<td colspan="2"></td>
</tr>
<tr>
<td colspan="2"></td>
</tr>
<tr>
<td colspan="2"></td>
</tr>
</table>

Answer 1

<table border="1">
<tr> <!-- row with 3 columns -->
<td>1x1</td>
<td>1x2</td>
<td>1x3</td>
</tr>
<tr> <!-- row with only 2 columns, where the second column is as wide as the second and third column, above -->
<td>2x1</td>
<td colspan="2">2x2</td>
</tr>
</table>
This is how to get a table with N rows and 3 columns. Is it what you were asking for? It would be useful if you could paste some code!
See this page to learn more about colspan:
http://www.w3schools.com/tags/att_td_colspan.asp
EDIT:
In your code you have written the table to display only 2 columns for every row.
You have to add a <td> tag to display another column per row.