Andrey Kolmogorov was a Russian mathematician. He was very good at math and he figured out a way to explain how probability works. He came up with a way to describe how certain events are more likely to happen than others. For example, if you flip a coin, chances are it will come up heads 50% of the time and tails 50% of the time. This is called the Law of Large Numbers and it was a big discovery at the time. Andrey Kolmogorov was a great mathematician who discovered a way to explain probability which helped us all better understand how the world works.