Entering superscript text (exponents) in TextEdit?
You can superscript style any text by highlighting the text and then selecting Format -&gt; Font -&gt; Baseline -&gt; Superscript from the menu in TextEdit.

It's not assigned to a keyboard shortcut by default. To assign it to a keyboard shortcut go to System Preferences -&gt; Keyboard and click on the Keyboard Shortcuts tab. Select Application Shortcuts from the left hand list and press the + button button below the right hand list to add a new application-specific shortcut:



From the menu that pops up select TextEdit as the application (otherwise the shortcut will be made for all applications). For Menu Title enter Format-&gt;Font-&gt;Baseline-&gt;Superscript and for Keyboard Shortcut (assuming OS X 10.8 or higher). Put your cursor in the box and press the combination of keys you want to use for the shortcut (I used Cmd+Shift+= in my screen capture example):



Press Add button to store the shortcut. You might have to restart TextEdit for the shortcut to appear.