PR is how important Google gives to your page. And PR toolbar does not exist and it is an incorrect term. The correct term is Google Toolbar that can also show you the PR.
__________________
All there is to know about interior design and decorative tips.
In autumn some birds must travel for miles and miles, all about bird migration.
You need not be confused between these two terms.
PageRank is what is continuously updating at the backend and is a decimal number while toolbar PageRank is something that updates after every 3-4 months and is visible to us .
Pagerank is very difficult algorithm. In short the more websites are linking to your domain the higher pagerank will your site get.
If you install Google toolbar you will see the toolbar pagerank value. It is good tool for webmasters to get an idea how important is the visited website.
It's easy to understand. Page rank is website's popularity according to search engine and through which tools we know our page rank is called page rank toolbar.