The mathematician Edward Kasner asked his young nephew, Milton Sirotta, to name a 1 followed by a hundred zeros, and the boy said googol. Then he offered a bigger one, the googolplex: a 1 followed by as many zeros as you could write before you got tired. Kasner kept the name and threw out the definition, and his reason, as he and James Newman told it in their 1940 book, was a fair one: different people get tired at different times, and it would never do for a prizefighter to own a larger number than a mathematician just because he had more stamina. So the googolplex became a 1 followed by a googol zeros, which is far more than anyone could write. The boy’s number was not so much too vague as too small, and the fair fix turned out to be one that wears out everybody equally.