In edit mode of WordPress the post would look just like this in the visual tab.

Notice the anchor icon in the picture below:

An anchor is how the system knows where to jump to.

To look at this a little further then we will look at the Text side of the post editor.

Here is the same post and section using the Text editor.

In short, the text code that is use for the anchor is of my post is:

<h3><strong> <a name="Internet-Jetset-Review"></a>Internet Jetset Review</strong></h3>

Note: My example is of a header 3 use a bold content so this can be done after you link to make the coding easier.

The base coding looks like this with no header 3 tag or bold tab in the code

<a name="Your-Description"></a>Your Description

Change your description to whatever your heading is about or point where you want to link to.

Note: This is just the anchor peice of the equations