I learned the following trick for memorizing the value of *e* from my colleague, Gene White. It never fails to impress calculus students (given a wide enough definition of “impress”).

Start by carefully looking at this picture:

That’s a **20** dollar bill, so memorize “2″ and put down the decimal point.

The picture on the bill is of Andrew Jackson. He was our **seventh** President, so put a “7″ after the decimal point to get** 2.7.**

Jackson was elected in **1828**, so put down “1828″ next. Since there’s a 2 in front of the decimal place, put “1828″ a second time. We’re now up to **2.718281828**.

Now look at the red square over Jackson’s face. The diagonal creates two congruent right triangles with angle measures **45, 90, and 45**. So, add on 459045 to get **2.718281828459045**. And that’s *e* to 15 places.

I’m open to suggestions on how to memorize more of the digits.