Pi Approximation Day on July 22 honors the concept of pi, denoted by the Greek letter pi and approximates to 3.14, in the most mathematically appealing way. Whether you're a baker or a math expert, this is your day. Pi is the fraction 22/7, which roughly translates to 3.14, representing the connection between a circle's circumference and diameter. One of the most well-known mathematical constants is an irrational number whose digits randomly repeat and never come to an end.

**Difference between Pi Day and Pi Approximation Day:**
Although Pi Day is most usually celebrated on March 14, related events have also been conducted on other days. Pi Day, is a day to celebrate the mathematical constant pi (π) and to eat lots of pie. The first Pi Day celebration was held at the San Francisco Exploratorium in 1988 and was the brainchild of physicist Larry Shaw. On March 11, 2009, which was almost precisely twenty-one years later, the U.S. House of Representatives passed a resolution designating March 14 as National Pi Day.
Pi Approximation Day is celebrated globally on July 22 each year. There is a special reason why this day is observed on July 22. The fraction 22/7 is an approximation of Pi. Because the proportion 22/7 represents the pi value, this day is observed annually on July 22.

**Move to Replace Pi**

In recent years, some mathematicians and physicists have argued for the replacement of the π by tau and to celebrate Tau Day on June 28 instead of celebrating Pi Day or Pi Approximation Day.