Google’s Built in Calculator

I just discovered, at Web 2.0 from Russia, that Google has a built in calculator!  Go to Google and search for sqrt(-4).  It even seems to give the correct answers, so far.  If you really wanted to search for documents containing sqrt(-4) then search for +sqrt(-4).  You can also do unit conversions and calculate currency exchange rates.

Here are instructions on correct syntax as well as another 3^2 examples.  Now I just need to figure out how to best use this feature in the classroom.

Note:  It doesn’t do as well with undefined terms such as 0/0 or 0^0.