Google has a calculator built into its search engine. Apart from the basics it can also be used for unit conversions, etc. Usually I’d say that’s very nice and can be handy considering just about everything has a google query form attached to it these days.

However..

What do you think would be the result of

1 - 0.9 - 0.1

?

Depending on the order of evaluation you’d say either 0 or 0.2, right? Well, you’re wrong. It’s -2.77555756 × 10e17. Because Google says so. Try it.
http://www.google.nl/search?q=1+-+0.9+-+0.1

It gets the answer to 1 – (0.9 + 0.1) right, but anything else is off.

1 - (0.9) - (0.1)
(1 - 0.9) - 0.1

etc.

A mountain full of PhDs and what do you get? A variation on pi = 3.