# The Strange Thing Hidden Behind the Pi (π) Number

## Although pi numbers are made up of endless strings of unpredictable numbers, they are not random numbers as we think. The pi actually contains all sorts of surprising models.

Over thousands of years of study, mathematicians have worked hard to find the mystery of** pi (π).** The pi is known to have a value of **3.14** and the decimal point is over **13 billion digits**. This is a calculated effort by researchers to make pi more accurate. Since the 18th century, people have known that they can never calculate all digits of pi. Because pi is an infinite number that goes on endlessly and does not have a certain rule.

In 1888, the** Mathematician John Venn**, the creator of the Venn diagram, attempted to show visually that the digits behind the decimal of pi were purely random. He drew a graph showing the first **707 decimal places**. He uses straight lines with directional arrows to denote **digits from 0 to 7** and then straight lines to represent the path of each number. Venn did this work with pen and paper but today modern technology has helped to create more detailed and beautiful models. Although pi numbers are made up of endless strings of unpredictable numbers, they are not random numbers as we think. The pi actually contains all sorts of surprising models.

## Normal but not random

The reason we can not call pi is random because its digits are determined correctly and fixed. For example, the second decimal place out of pi is always 4. So you can not ask the question is the other numbers can be placed in this position? This is not a random place.

But we can ask a related question:* “Is Pi a normal number?”* A decimal number is considered normal when each sequence of digits has the same probability of occurrence, making them seem random – no matter the truth. By looking at the digits of pi and applying statistical tests, we can try to determine whether pi is a normal number. From the tests done so far, this is still an unanswered question in the end.

**For example,** in 2003 Yasumasa Canada published a statistics table showing the occurrence of different digits in the first billion digits of pi: Number / Occurrence

**0 / 99,999,485,134****1 / 99,999,945,664****2 / 100,000,480,057****3 / 99,999,787,805****4 / 100,000,357,857****5 / 99,999,671,008****6 / 99,999,807,503****7 / 99,999,818,723****8 / 100.000.791.469****9 / 99,999,854,78**

### Total of 1,000 billion

The results of his research indicate that these numbers seem to be fairly evenly distributed. It is not enough, however, to prove that all pi numbers are normal.

## Each number sequence

There is a surprising fact that, if pi is a normal number, then for any sequence you can call, you find pi. For example, at position **768** in the pi digits, there are six 9 numbers appearing consecutively. The opportunity for this to happen (with pi being a normal number) and each sequence of n digits can occur in equal measure –** 0.08%**. Following Richard Feynman’s Nobel Prize, this nine-digit group is known as the **“Feynman Point.”** Feynman once joked that if he had to reread the pi numbers, he would name them and then call them “so on.” Other interesting sequences have also been found. At the position of **17,387,594,880** you find the sequence number **0123456789**, and surprisingly in position 60 you find these ten digits are arranged in order. Those who seek and study pi number ask: **“Where can I find pi numbers?”** If you want to check whether special numbers are pi or not, you can use the free online software called Pi Birthdays.

The number** pi (symbol: π)** is a mathematical constant equal to the ratio of the circumference of a circle to the diameter of that circle. This constant has an approximate value of **3.14159265358979**. It is represented by the Greek letter **π** from the middle of the 18th century.