Pi Day 2025 is a mathematical wonder

by Aziz Inan of California Eta

The number 𝝿 is a mathematical constant that is the ratio of a circle’s circumference to its diameter, approximately equal to 3.14. The number 𝝿 appears in many formulae across mathematics and physics.

Pi Day is an annual celebration of the mathematical constant 𝝿 observed every year on March 14 since the digits of this date expressed in the month/day format as 3/14 constitute the first three significant digits of 𝝿.

This year, Pi Day expressed as 03/14/25 is a mathematical wonder. Why?

First, the digits of 03/14/25 consist of whole numbers 0 through 5, each appearing only once.

Second and more exciting, if the first six whole number sequence {0, 1, 2, 3, 4, 5} is split in the middle into two sequences consisting of {0, 1, 2} and {3, 4, 5}, these two sequences intertwined with one another yield 031425, representing the date of Pi Day, 03/14/25 (see figure).

This captivating hidden property of 03/14/25 is fascinating! It is like a mathematical puzzle. A special property is secretly coded in the sequence of the digits, and one must untangle this pattern to be able to uncover its beauty.

The unique feature of Pi Day in 2025 can draw more attention to Pi Day and has the potential to serve as a factor in attracting more students to fields in STEM.

I hope you acknowledge this year’s unique Pi Day and advocate for its recognition because this one of a kind Pi Day occurs only once in each century in the year ending with 25. Most people won’t experience this day again in their lives except those few who may live at least another hundred years after 03/14/25 and experience it in 2125.

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For more detailed information about the rarity of this year’s Pi Day, be sure to read the extended article from Aziz Inan to be published in March 2025 Bulletin.

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Aziz S. Inan, Ph.D., CA H ’78, received his B.S. degree in electrical engineering from San Jose State University in 1979 and M.S. and Ph.D. degrees in electrical engineering from Stanford University in 1980 and 1983, respectively. He joined the electrical engineering department at University of Portland in 1989 where he is currently teaching as a professor. He is the coauthor of three textbooks in electromagnetics published in 1999, 2000, and 2015. He received the University of Portland Annual Outstanding Faculty Teaching Award in 1992 and the Associated Students of University of Portland (ASUP) Faculty of the Year Award in 2005. He is a valued member of Tau Beta Pi and life member of IEEE.