If you want to fight the city about red-light cameras, you better make sure your math is good to go. That’s the message sent by a state appeals court last week as it affirmed a man’s red-light camera citation, in part because his expert video analyst miscalculated the length of a yellow light. The 1st District Appellate Court ruled that Bohdan Gernaga’s $100 fine for entering an intersection during a red light was not against the manifest weight of the evidence, siding with an administrative law …