The sound of numbers crunching could be heard all over the city last week. Mayor Bloomberg agreed to pick up Merrill Lynch’s 20 percent stake in Bloomberg LP for $4.4 billion — which values the company at $22.5 billion and jumps his estimated net worth to somewhere around $20 billion. Wacky Iranian president Mahmoud Ahmadinejad estimated that September was a good time for a return visit to the Big Apple. A $52 million fund-raising month helped Barack Obama recover from being offended by The New Yorker’s controversial cover cartoon. Fed chairman Ben Bernanke bailed out troubled mortgage lenders Fannie Mae and Freddie Mac, while news broke that the consumer price index is rising faster than it has since 1982.

Representative Charlie Rangel declined to renew the lease on the rent-stabilized Harlem apartment he’d been using as an office. Two unexplained charges at the infamous Mayflower Hotel showed up in filings from the defunct Spitzer 2010 campaign. Former State Senate majority leader Joseph Bruno cleaned out his Albany office in a hurry, perhaps to cash in on a $95,000 annual pension. Five child-welfare workers were charged with skimming $1.5 million to cars, including an $84,000 BMW. A judge questioned Patricia Duff’s choice to represent herself in a custody battle against billionaire Ron Perelman.

A graphic designer in midtown bit into his fresh-baked Subway sandwich only to find a serrated knife with a seven-inch blade had been baked inside. Rocco, the beagle who wandered from Queens to Georgia and back, weighed offers to tell his story. SNL’s Amy Poehler signed on to star in a sitcom from the producers of The Office. A Rod’s lawyer insisted that reports of domestic surveillance among the Rodriguez clan were in error. Boss George Steinbrenner emerged from seclusion to make an appearance at the marathon All-Star Game. And first-night showings of The Dark Knight sold out all over town, on word of mouth about Heath Ledger’s unhinged final performance as the Joker. —Mark Adams