Looking for a fast way to do basic calculations whilst working on your Mac? There’s the calculator widget, and then there is the Calculator.app built into OS X. But both of these require jumping to some other location or application on your Mac. What about an even easier solution?
Hit Command-Space to bring up Spotlight (top right corner of your screen) and start to type in a calculation. For instance, if you type in 4573*3847 it will show you the result. Easy.