The Google search site has a built in calculator. Simply type in a math problem and the search results will be the answer. I found this by accident when I was trying to search a phone number. Because of a typo which caused a missing hyphen I entered the number 843524-6198. Google treated it as a math problem and return the results of
843524 - 6198 = 837326
Neat, yuh? It is not as handy as window's built in calculator, or having a hand calculator on you desk, but still neat. If you are not sure which function to perform first type out the problem and Google will but the parentheses in for you.
58*62-52/8+5681 = (58 * 62) - (52 / 8) + 5681 = 9270.5