The wordpress environment is not perfect when you need to do some specific layout within a document. The div tag is a flexible html tag when combined with CSS.
This is one way to add more control within a post or a page. For example how about a picture in a post and some text to the right.
First CSS is the feature that gives visual and design control to HTML.
The way to add CSS to a div tag is to use the style command.

Here’s the code:
<div style="float:left;"><img src="/wp-content/uploads/2012/04/Train-RGB-799882.jpg"></div><div style="float:left;">This is the text</div>
