Do you like Pi?
Do you like Pi? Bpost issued five Pi stamps in a sheet on August 25, 2025. A beautiful design by Geert Wille, who incorporated the magical 3,14 into the sheet of 5 stamps. Why are Archimedes and Albert Einstein included in this issue? Why is Pi Day celebrated worldwide on March 14? These are all questions this blog answers.
Do you like Pi?
At the top, clockwise, the descriptions: A. Portrait of Archimedes. Archimedes was the first to accurately estimate the value of pi by using a method in which he approximated the circumference of a circle with polygons, both inside and around it. He used a polygon with 96 sides and determined that pi lay between the fractions 223/71 and 22/7, which was an accurate approximation for that time. B. Calculation of the area of a circle. C. Portrait of Albert Einstein, made up of the digits of pi.
Albert Einstein was born on March 14, 1879. Pi Day is celebrated on March 14 (dd/mm = 3,14). D. Symbol for the number pi, plus the number itself E. Artistic interpretation of the symbol for Pi Sheet margin: A blackboard showing calculations involving pi, or references to the number. Details: A round sheet with round stamps. Price: 5 x value 'World 1' = 15 euros. Stamp: 31,4 mm Ø Sheet: 148 mm Ø
Pi Day
Pi Day and Pi Approximation Day are two holidays dedicated to the mathematical constant Pi. Pi Day is celebrated on March 14 celebrated in various ways. For instance, some reflect on the role of Pi in their lives and try to humorously imagine “a world without Pi.”
Pi Day, the fourteenth day of the third month, is celebrated worldwide in university mathematics departments. The number sequence follows the date format year/month/day, for example 2025/03/14. This is because the three-digit approximation for Pi is 3,14.
The celebration usually begins at 1:59 AM or PM, because that is the six-digit approximation of Pi, 3,14159. The “ultimate Pi moment” was on March 14, 1592, at 6:53:58 seconds; in the order month/day/year/hour/minute/second, this corresponds to the first twelve digits of Pi: 3,14159265358.
A few years ago, schools and universities in America began celebrating Pi Day by eating pie (in English, the letter pi is also pronounced that way by English speakers) or pizza. Food items are made in the shape of a Pi symbol and games are played.
During the UNESCO conference in November 2019, March 14 was declared the International Day of Mathematics (IDM). Albert Einstein was born on Pi Day, March 14, 1879.
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