"How're you going?"
"I can see that. How much did you drink?"
"Well I had four beers but I poured half of one away so it was three and a half beers and then wanted a coke but he bought me another beer so I had three and a half beers plus one beer."
"So four and a half beers."
"No, it was three and a half plus one."
"Four and a half, then."
"It might have been seven."