Mac OS X Leopard has hundreds of features. Some of these go by unnoticed, even when mentioned in the full list on Apple.com. One of these features is the Spotlight calculator. If you a type simple problem into Spotlight the first result will be the answer. Same thing goes with words. If you type a word into Spotlight the first result is the definition, then you can click the definition to open it in Dictionary.app.
This is very useful to solve a problem quickly, and you don’t have to open any applications!

mozingeaux // 01/12/2007 at 4:34 am
I’m still running Tiger and in Safari I tried typing different things in the built-in Google search bar and I get similar results from Google, too. Awesome! Thanks for the tip!
Jack // 01/12/2007 at 11:11 pm
Oh, well I guess Google does it too.
marchputt // 07/08/2009 at 8:06 pm
spotlight on my mac didn’t working
can anyone help me about that?
A (fairly) simple equation evaluation service for Snow Leopard « Brett Terpstra // 31/12/2009 at 7:37 am
[...] mathematical symbols. Sure, there are plenty of ways to do calculations in OS X (Spotlight, Launchbar, Quicksilver), but I’ve had more and more incidents lately where I just [...]