Professional Development Hell

I had to do some PD the other day and was once again stunned at the limited knowledge of so many math teachers. TI-inspire had some terrible little app running that didn't really work properly but was purportedly able to help students correct their misunderstanding of some simple math ideas. One of these: what happens to area when you double the radius? Take a 7 inch circle and drag the radius out to 14 inches and see what happens to the area.

"I don't get it. What's that mean -- area = 1.66E+2 inch² - what's the E thing?"

I guess we know why so many students have misunderstandings about math.