Bored? Mathematically inclined? Slate examines FL education commissioner Tony Bennett's charter-school defense and literally does the math.

"Florida Education Commissioner Tony Bennett resigned Thursday amid claims that, in his former position as superintendent of public instruction in Indiana, he manipulated the state’s system for evaluating school performance. Bennett, a Republican who created an A-to-F grading protocol for Indiana schools as a way to promote educational accountability, is accused of raising the mark for a school operated by a major GOP donor. Bennett calls that charge, which arose from emails among Bennett’s staff obtained by the AP, “malicious and unfounded” and “frankly so off base.” He offered a different explanation for why the grades for Indianapolis charter school Christel House Academy—whose mark soared from a C to an A—and 12 other schools were changed at the last minute. According to Bennett, he was just correcting a simple math mistake." -- Jordan Ellberg,