What is the chance that a random number starts with the digit "1", the number "3" or "7"? If you are familiar with the probability theory, it can be assumed that the probability is one to nine, or about 11%.
If you look at the real numbers, you'll notice that the "9" occurs much rarer than in 11% of all the cases. In addition, far fewer numbers than it was expected, start with "8", but a 30% of numbers begin with the "1". This paradoxical pattern appears in all sorts of real-world cases, starting from the number of the population and finishing with the stock price and the length of the river.
The physicist Frank Benford first noted this phenomenon in 1938. He found that the frequency of digits as the first drops as the number increases from one to nine. That is, "1" appears as the first digit of about 30.1% of the cases, "2" appears around 17.6% of the cases, "3" - approximately 12.5%, and so on through "9" serving as the first digit only 4.6% of cases.