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Maths made interesting, even for the number-phobic

May 23, 2014 15:14

BySimon Round, Simon Round

2 min read

What is your favourite number? Statistically, it is likely to be 7, according to research by Alex Bellos, the author of this follow-up to his popular book on maths, Alex in Numberland.

There are various reasons for this but the Jews played their part with the invention of the seven-day week. There are also the seven deadly sin, the seven seas and the seven dwarfs. Odd numbers are psychologically more attractive to many of us and in certain cultures they dominate — you will look in vain for a plate with an even number of sushi in a Japanese restaurant.

However, the significance of numbers, and their order, goes well beyond the psychological. If you look at any data, from the Domesday Book to stats in the FT, you will see that 1 is the most common number, 2 is the second most common, 3 the third most common.

Not only that but their ratio is pretty much constant: 1 will occur around 30 per cent of the time, 2 around 18 per cent and so on. This, I discovered, was Benford’s Law and has applications in forensic accounting. If the numbers in a financial report are out of synch, it is a pretty good guess that someone is fiddling the books. This is the first “wow” moment in the book but by no means the last.

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