Whip out your TI-87 calculator this e-Day, February 7, and spot the little button that bolsters logarithmic and exponential functions on the daily. While you may not be too familiar with e, you’re surely acquainted with its more famous cousin, pi. Just like pi, e is an inexplicably recurring number in the world of mathematics. It has a never-ending chain of decimal points, the beginning of which is 2.718281828, and on and on it goes. This holiday is celebrated on 2/7 for the obvious reason that the date holds the same digits as e rounded to the nearest tenth.

History of e-Day

This complex algebraic riddle has been toyed with for over 400 years but has only fully been understood and defined for about 300. It first appeared in 1618 as a vague reference in the papers of Scottish mathematician John Napier. In a roundabout way, Napier hinted at the potential for a recurring constant by sharing a number of logarithms that he had solved using the number yet, infuriating many of his readers, he did not share the number itself.Later, in 1683, Jacob Bernoulli was officially credited for unveiling the analytical gem when he attempted to find the answer to a generic logarithmic expression, the answer to which was — you guessed it — e. For a brief time, followers of Bernoulli obscurely named the number b in their frequent correspondence. That was until Leonhard Euler ascribed the first letter of his surname to the constant and definitively named it the base of all logarithmic expressions in 1731. To this day, the constant is called e in remembrance of Euler.While e-Day cannot be traced back to any particular calculus enthusiast and we aren’t quite sure how long it’s been celebrated, we can understand the logic behind assigning this weight-bearing numeral to its digit twin. In 2018, a University of Portland student realized that the numeric date was 2/7/18, which also happens to be the first four digits of the beloved constant. Analytical minds all over the world were smugly pleased by this observation and constant e was perhaps more celebrated than ever before as many math-inclined minds discussed the coincidental alignment of such a calendar match-up.

e-Day timeline

Beating Around the Bush

While working with logarithms and exponents at the height of his career, John Napier unwittingly uses constant e to solve a series of equations.

Meeting of Chance

While calculating a problem about continuous interest, Jacob Bernoulli discovers the recurring numerical constant 2.7182818, or e.

Line in the Sand

After much back and forth for over a century, Leonhard Euler names e the basis for all logarithmic functions.

Numeric Irony

Sending many math majors into a tizzy, Aziz Inan of the University of Portland recognizes a ‘double consecutive e-day’ on 2/7/18.

e-Day FAQs

How many digits are in e?

Both Euler and lesser-known mathematician Fourier have proven that e is an irrational number, which means it has infinite digits.

Why is e special?

The number e is a famous irrational number and is one of the most important numbers in mathematics. e is the base of the Natural Logarithms.

Why is pi more popular than e?

We suspect that pi gets more screen time because it is primarily used in trigonometry, which is a much more accessible idea to the general public than exponential growth.

How to Celebrate e-Day

  1. Sharpen your mind

    For many of us in the adult world, it’s been ages since we sat down to solve an algebra or calculus problem. In a show of celebration this e-Day, take a seat at your desk and hone your rusty skills by calculating a logarithmic equation using the constant e.

  2. Memorize the digits

    We can all remember that one peer from school who knew 100 digits of the constant number pi. Give e a little love this holiday by memorizing its digits as far out as you’re able to. This will be a wonderful game to play with children or a good-hearted competition to engage in with friends. Who can memorize the most?

  3. Donate a calculator

    If there’s anything the ancestors of e would want, it’s more people falling in love with the clean lines and organization of mathematics. High-powered calculators are fairly expensive and not every student in your area will be able to afford one. Consider donating a calculator so that another person can relish in the puzzle of e.

5 Facts About STEM Field Workers That Will Puzzle The Mind

  1. Fat checks

    Those who graduate with degrees in science, technology, engineering, and/or mathematics (i.e. STEM) earn 26% more on average than their equally educated counterparts.

  2. Gender disparity

    Only about 25% of STEM workers are female.

  3. Not just engineers

    All medical fields, including nursing, surgery, and physical and occupational therapies fall under the STEM umbrella.

  4. Uneven distribution

    While some areas of STEM such as medicine and technology are experiencing a saturation of qualified candidates, others such as nuclear engineering are experiencing a severe lack of potential new hires.

  5. Early exposure

    According to childhood development professionals, the best way to encourage a STEM interest in children is to include them in cooking, building, and grocery shopping (i.e. money management).

Why we Love e-Day

  1. An overlooked number gets recognition.

    To mathematicians, e is an old friend. But to the rest of the world, e is the overlooked sibling of the much more extroverted and mainstream pi. By celebrating e once a year, we can finally give this constant the love and recognition it deserves.

  2. It’s a great reminder to sharpen our skills.

    To be honest, it’s been ages since we’ve picked up a calculator for anything other than addition and subtraction. Celebrating e gives us a reason to revisit those skills we learned so long ago in high school and college. Gotta keep the mind nice and sharp!

  3. Math determines much of life.

    Those of us who are not in the STEM field might make the mistake of thinking that such nuanced information doesn’t apply to us, but it most certainly does. On e-Day each year, we remember how vitally important the ancient study of mathematics has been to our civilization. Without it, our bridges wouldn’t hold steady, our interest rates would make no sense, and our grocery bills would be entirely unpredictable.

e-Day dates

Year Date Day
2023 February 7 Tuesday
2024 February 7 Wednesday
2025 February 7 Friday
2026 February 7 Saturday
2027 February 7 Sunday