- wearegoodatthis

# Feb. 7! e (Euler's number) Day!

**February 7 (2/7) is e (Euler's number) Day in America!** In countries that do the date as date /

month, *e* Day was on January 27 (27/1).

__What is e ?__

"**The number e is a mathematical constant that is the base of the **

**natural logarithm**

**: the unique number whose natural logarithm is equal to one. It is approximately equal to 2.71828**,[1] and is the limit of (1 + 1/

*n*)

*n*as

*n*approaches infinity, an expression that arises in the study of compound interest. It can also be calculated as the sum of the infinite series[2]

"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)."

https://en.wikipedia.org/wiki/E_(__mathematical_constant__)

"**So what is e good for?** See Exponential and Logarithmic Functions.

**It is used extensively in logarithms (which was the only way to do difficult calculations for hundreds of years before calculators came along), exponential growth (of populations, money or ****drug concentrations over time****) and complex numbers (which were used to design the computer or mobile device you are reading this on)."**

https://www.intmath.com/__blog__/mathematics/today-is-e-day-4133

**Plus Magazine: Living Mathematics website (link below) has a lot of good articles on e and its relevance in everyday life:** compound interest (money!), in nature and in science (e.g. radioactive decay, etc.)

https://plus.maths.org/content/__happy__-e-day

==

__For e day,__

**I made 2 cookies. I used the sugar cookie and non-Royal Icing icing for both cookies (link). **

https://www.__wearegoodatthis__.com/post/trying-out-cookies-icing-for-decorating-easy-sugar-cookies-non-royal-icing-icing

**One I made to resemble a chalkboard with e to 18 decimal points. **To get the white icing to show up, I had to let the black background set completely and then do the white icing later.

**The other I made to resemble a TI-83 calculator, which I used growing up when I was first learning about e. It's a little rough looking. Haha. :) **For the calculator, I made the buttons out of marshmallow fondant (link).** **I could have made the buttons more regularly shaped, but I got tired. Haha. :)

https://www.wearegoodatthis.com/post/can-i-make-__marshmallow__-fondant

Happy *e* day! Give it a try! We are good at this!