Type 45+12 into Google. What do you get? Well, you’re just going to see a listing of sites that contain that term. Wrong. Google is smart enough to invoke its calculator when you type a mathematical expression. So the result you get is 45+12=57. Neat.
Can’t find something on a website but you’re pretty sure it’s somewhere on it? Type the term you’re looking for and follow it with site:thesite.com. For instance, if you want to find out all the sites on this domain that I mention my wife (please don’t do this , type marta site:lifelonglearner.kubasek.com. I’m going to get killed…
Another cool thing is safe search. Let’s say you need to search for sex education but you’re not interested in all of the porn sites. Type safesearch: sex education. This will filter out the adult sites from your search.
This and couple more that you might find useful are on Google Help: Google Cheat Sheet.