In a bean machine or Galton box most balls end up close to the center. In the long run, they will show a normal distribution

Probability is a part of applied mathematics. It has to do with chance, the study of things that might happen or might not happen.

For example, using probability, one can show that by throwing a coin up in the air and letting it land, half of the time it will land with one side facing up, and half of the time with the other side facing up. Many coins have a picture of the face of a famous person on one side, and something else on the other side. Often people call the side with the face "heads", and the other side "tails".