Last November, Unesco approved March 14 of every year as International Day of Mathematics (IDM) to celebrate its beauty and importance in everyone’s life.
March 14 is already known as Pi Day (3.14…) and celebrated yearly worldwide. The IDM (#idm314) celebration expands Pi Day to include the many other areas of mathematics with a new theme every year. The theme of the first celebration in 2020 will be “Mathematics is Everywhere”, where activities and celebration will focus on showing how mathematics and its applications are in every aspect of our lives.
One of the examples of “Mathematics is everywhere” is in fraud detection, especially in financial statements when someone has manipulated the data without taking care of the laws of numbers. One law is Benford’s Law (first digit law), which is a probabilistic law. To explain Benford’s law, consider any large numbers around you (house prices, electricity bills or all numbers you find in this issue of the newspaper) and look at the first leftmost nonzero digit (significant digit), for example, in 435.687 the significant digit is 4 and that of 0.000125 is 1.
Benford’s law states that one should get approximately 30% of digit 1 and only 4.5% of digit 9. This means random large numbers will likely start with small significant digits. If the data doesn’t look anything like the distribution predicted by Benford’s Law, it may mean the numbers have been manipulated.
In movies, Ben Affleck in the movie The Accountant (2016) uses Benford’s law to expose the theft of funds from a robotics company where he identified a series of suspicious transactions by the unusual frequency of the number three in their dollar values.