May 18, 2009 5:32 pm 7th Grade Math? There's an App for That Two enterprising Chicago 7th graders have developed their own application that turns your iPhone into a math tutor — and they’re dividing the profits by two. Local 3:10 Suspect charged in killing of Chicago police officer faces additional charges 2:03 Prosecutors detail how Calumet City cold case unfolded, with suspect finally arrested 0:54 Richest person in Illinois revealed in new Forbes Magazine ranking 1:45 Video shows arrest of suspect in CPD officer Luis Huesca's murder 2:25 Thursday afternoon forecast