A missed opportunity to teach some mathematics

I’m surprised that I missed this scandal in the aftermath of Hurricane Sandy:

To deal with fuel shortages after the storm, New York Mayor Michael Bloomberg introduced rationing on 8 November.

“Drivers in New York City who have licence plates that end in an odd number or end in a letter or other character will be able to gas or diesel only on odd-numbered days such as tomorrow which happens to be the 9th,” he said.

“Those with licence plates ending in an even number, or the number zero, will be able to buy gas or diesel only on even number days such as Saturday November 10th.”

I knew about the rationing. The scandalous part is that Bloomberg uttered the phrase “an even number, or the number zero.” I suppose you could argue that it’s technically correct (as long as the word “or” is inclusive), but it certainly seems to imply that zero is not an even number.

It’s probably true that lots of people don’t know that zero is an even number, so including the clarification makes sense. I just wish Bloomberg had taken the opportunity to educate people a bit by saying “an even number, including zero” instead of “or zero.” He may, inexplicably, not have thought that this was a priority under the circumstances.

By the way, before you use this as a jumping-off point for a jeremiad about the sorry state of American mathematical knowledge, I should point out that this is not an exclusively American problem. From the same BBC report:

It’s not just the public who have struggled to recognise zero as an even number. During the smog in 1977 in Paris, car use was restricted so that people with licence plates ending in odd or even numbers drove on alternate days.

“The police did not know whether to stop the zero-numbered licence plates and so they just let them pass because they didn’t know whether it was odd or even,” says Dr Grime.


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Ted Bunn

I am chair of the physics department at the University of Richmond. In addition to teaching a variety of undergraduate physics courses, I work on a variety of research projects in cosmology, the study of the origin, structure, and evolution of the Universe. University of Richmond undergraduates are involved in all aspects of this research. If you want to know more about my research, ask me!