# Jan27 Fun Holiday – e-Day

e-Day celebrates the mathematical constant e, which has a value of 2.7182818. It is celebrated on February 7 in countries that follow the month/day (m/d) date format. This is because the first two digits of the date - 2/7 - correspond to the first two digits of the constant.

People living in countries that follow the day/month (d/m) format celebrate it on January 27. The first three digits of this date - 27/1 - match up with the first three digits of e (2.71).

## Euler’s Number

Also known Euler’s number, after the Swiss mathematician Leonhard Euler, e is an irrational number that represents the idea that all continually growing systems are a scaled version of a common rate. It is mostly used in logarithms, exponential growth, and complex numbers. It is one of the most important numbers in mathematics, including 0, 1 and pi (π).

e is also sometimes called the Napier's Constant and is often incorrectly referred to Euler's Constant. Euler's Constant is denoted by lower case gamma (γ) and has a value of 0.57721.

## Other e Days

Many European countries celebrate Euro Day, sometimes also called e Day. The day is observed on January 1 and celebrates the anniversary of the adoption of the Euro, Europe's common currency in 2002. In New Zealand, eDay is a day where people can get rid of e-waste or old electronics such as computers and old appliances so they can be recycled rather than being placed in a landfill. Engineer’s Day is observed in Paducah, Kentucky on February 21, where many people participate in an egg drop contest, create edible cars, and tape people to walls.

## Other Mathematical Holidays

The year is full of mathematical and scientific holidays. Some of these include: Yellow Pig Day, Mole Day, Fibonacci Day, Palindrome Day, and Pi-Day. Use our Date Pattern Calculator to find out other interesting calendar dates during the year.

## How to Celebrate?

• Celebrate this fun mathematical holiday by learning more about Euler's number and its importance in mathematics and science.
• Eat foods that begin with e - make eggs, eggplant, or eclairs. Make eggnog as a before dinner refreshment or eggs benedict for breakfast.

## Did You Know...

...that there is an island in northern Scotland called Eday?

## e-Day Observances

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## Other Fun Holidays around January 27

### Opposite Day

Celebrate all things contradictory, opposing, conflicting and inconsistent on this contrary holiday.

### Spouse's Day

Show your significant other your utmost love and appreciation on this unofficial holiday especially created for them.

### Chocolate Cake Day

Celebrate everyone’s and their grandma's favorite cake

### Data Privacy Day

Take steps to protect your offline and online data.