I demonstrated running, editing and refactoring calculations in my OSCON Talk 
. I created this site so others could try duplicating the changes.
This wiki uses plugins to add data, computation and visualization. I demonstrated a simple calculator starting with the documentation page inherited by any instance with the plugin installed.
Try editing the simple sum offered as an example in the above documentation page. Double-click the gray box to edit. Type Command-S to save.
Your browser will keep your changes indefinitely. You can Remove Local Storage Pages if you'd like to restore this site to its original condition.
The plugin documentation includes a second page that shows datasets and calculators cooperating to complete the 99 Bottles of Beer song in record time.
The calculations for this song can be simplified. I demonstrated that the -1 increment need only be specified once. Try removing the -1 from subsequent verses. It should still compute.
I also showed that the various parts can come from different pages. For example, here are some pages that don't exist yet.
Click these links to create the pages. Refactor by dragging the beer constants and final verses to them.
If you don't get the results you expect, try opening the pages in a different order. Use Shift-Click to follow the above links without removing pages already clicked, or, edit pages to include a link to the appropriate next page to open.