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Jul22 Fun Holiday – Pi Approximation Day

July 22 is Pi Approximation Day. Also known as Casual Pi Day, the day is dedicated to the mathematical constant pi (π).

Celebrate pi (π) by eating lots of pie.

Pi denotes the relationship between a circle’s circumference and its diameter and is denoted by the fraction 22/7 which calculates approximately to 3.14. One of the most widely recognized mathematical constant, π, is an irrational number, the digits of which repeat in a random fashion and are never ending.

Depends on Date Format

People in countries that write their dates in the date/ month format celebrate Pi Approximation or Casual Pi Day on 22 July or 22/7. On the other hand, those who write their date in month/ date format celebrate Pi Day on March 14 (3/14 or 3-14) because the first three digits of the date correspond to the first three digits of pi - 3.14.

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.

How to Celebrate?

Here are some ways you can celebrate this irrational, but fun holiday:

  • Celebrate the day with lots of pie – remember a pie is also a circle so not only are you learning something about math, but also having fun while eating it!
  • Have a pi contest. Whoever knows the most digits in the number takes home a pie.

Did You Know...

...that the sequence 123456 does not occur in the first million digits of pi?

Pi Approximation Day Observances

Fun Holiday: Pi Approximation Day Observances
YearWeekdayDateName
2020WedJul 22Pi Approximation Day
2021ThuJul 22Pi Approximation Day
2022FriJul 22Pi Approximation Day
2023SatJul 22Pi Approximation Day
2024MonJul 22Pi Approximation Day
2025TueJul 22Pi Approximation Day
2026WedJul 22Pi Approximation Day
2027ThuJul 22Pi Approximation Day
2028SatJul 22Pi Approximation Day
2029SunJul 22Pi Approximation Day

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