E-Day
Every year on February 7, math gets its own birthday party. Pi Day hogs the spotlight on 3/14, but February 7 quietly does the same trick for another famous number. Written in month-day form, 2/7 echoes the first two digits of the mathematical constant e, about 2.718. It is a day for exponential enthusiasts and calculator romantics, and for anyone who ever raised something to a power and felt a little thrill.
- Roots
- A grassroots math holiday built on the date 2/7, the start of e = 2.718...
- Also on Feb 7
- Ice Cream for Breakfast Day · Fettuccine Alfredo Day · Periodic Table Day
- Hashtag
- #EDay
3 ways to celebrate
Mark the Moment at 18:28
Set a timer for 18:28 on February 7, the hour that turns 2/7 into 2.718, and toast the constant with coffee and a blank notebook. Try writing the digits of e from memory to see how far you get.
Bake an e Cake
Ice the digits 2.71828 onto a cake or pizza and challenge friends to each recite one more digit than the last. The loser refills the coffee.
Run a Growth Experiment
Walk through Bernoulli's compound interest discovery: compound a dollar in ever smaller fractions and watch the total approach e. It is the most memorable math lesson of the winter.
Fast facts
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