I ran across this behavior in FireFox today. Google suggest pops up when you start typing a search query in the upper right corner of the browser.
Type in a math string and the answer will pop up in the suggest box with an '=' sign in front of it at the top of the list.
This will also work with some of the converters, i.e. 1 km in miles, 37C in F, 1 hectare in acres, etc, etc... [37C in F] --> '= 98.6 degrees fahrenheit'
This functionality may also appear in other browsers with the google suggest feature.
I thought this was pretty cool, I hope you enjoy it too.