A recurring theme in our class is the use of mathematics to understand the world - think back to how demographic math made the French and Indian War inevitable, how Thomas Paine argued that mathematically America was predestined for independence, how the math of the Northwest Ordinance reflected northern values, and how the math of tariff policy contributed to industrial growth.
But we should also be wary of numbers. Like all other primary sources, mathematical data may not be valid (think of the "citizenship poll" we covered - it was not what it said it was) or unreliable - presented in a way that is intended to mislead. I doubt if this pie chart falls into the "intended to mislead" category; I suspect it is just an example of some news staffer who failed math class.
What's wrong with this pie chart? Bragging rights go to the first person to post the problem in the comments section.
The chart image is from here. Lead from Volokh.