This week PolitiFact gave us a terrific example of PolitiMath.
Obama said, "We’ve got close to 7 million Americans who have access to health care for the first time because of Medicaid expansion."Obama's 7 million figure exaggerated the high-end accepted estimate of 1.8 million by 288 percent. PolitiFact calls that "False." Not ridiculously false ("Pants on Fire"), but simply false.
...The actual number is estimated to be between one-seventh and two-fifths of what Obama said it was. We rate the claim False.
File that one away for future, and past, reference.
Update Feb. 26, 2014: Eliminated some extraneous html coding that ended up visible in the text, and also altered the quotation of PolitiFact to make clear it draws from two different paragraphs.