How many grains of sand are there on the beach at Coney Island in New York City? How many raindrops fall on London in a year? What is the number of words that have been spoken in all the history of mankind? How many electrons are there in a thimbleful of air?

In order to answer questions such as these, mathematicians often have to deal with very, very large numbers. To help them do it, the American mathematician Edward Kasner coined a name for a very, very large number: the googol. A googol is a hundred billion billion, which is a 1 followed by 100 zeros

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