Sum guy tests NYC

New York's bustling pedestrian traffic has come to a standstill in Times Square, where a crowd is deliberating the proposition: "If Pete sells a 6in pizza for $6, how much should he charge for a 12in pizza?"

But Pete is not a street trader trying to make a fast buck, writes Jon Marcus. The question has been posed by George Nobl, a professor of mathematics at DeVry Institute, who sets up an easel each Wednesday at lunchtime on 42nd Street between 5th and 6th avenues and poses questions such as this, competing with hawkers selling baubles and umbrellas.

People who answer correctly receive a candy bar. Dr Nobl said Americans were afraid of maths, which he believes accounts for the fact that they do not understand it very well.

"And if this keeps going, we're going to fall behind very badly," he said.

People on the street are challenged: "Come on up! You think better up front."

Dr Nobl said he wanted to make maths fun.

He is seeking grants for a non-profit group he hopes to found, which would set up easels like his and engage passers-by with maths questions all over New York City.