When I found that tip out, my internet use changed. My old work computer lacked a calculator program. It was annoying. Then I found out that I just had to input my equation into Google's search feature and my answer was spit out. Wonderful!
Google's calculating function goes beyond basic addition, subtraction, and multiplication. You can use the full range of mathiness that is out that. For example, you could type "5*9+(sqrt 10)^3=" and receive the (correct) answer of 76.6227766.
The equals sign is the key. That is what tells Google you are doing some math and not searching for a random numerical phrase. Check it out!