Library›Numbers with Stories›One card

A LITTLE SOMETHING WORTH KNOWING

A small discovery. Yours to pass on.

Math & LogicOne small ahaNumber

This constant, written e, is the base of the natural logarithm.

Think it. Then flip it. ahamoraTap to reveal Back to the cue
Math & LogicOne small aha
Your new ahaEuler's Number

Euler's Number — value or symbol: e ≈ 2.71828. Source: E (mathematical constant) ↗

ahamoraReference ↗

Keep the thread going

One answer is a beginning.

Share a little curiosity, or follow it into the full collection.

Flip the full deck →

More from Numbers with Stories

A few more worth knowing.

  1. 03This ratio equals (1 + √5) / 2 and divides a line so that whole-to-longer equals longer-to-shorter.RECALL
    The Golden Ratio

    The golden ratio, prized for its pleasing proportion, appears in certain natural growth patterns.

    Open this card ↗
  2. 04These integers greater than one have exactly two positive divisors: one and themselves.RECALL
    Prime Numbers

    Prime numbers have exactly two positive divisors: one and themselves. The number one is not prime.

    Open this card ↗
  3. 05Starting with 0 and 1, each term of this sequence is the sum of the previous two.RECALL
    The Fibonacci Sequence

    The Fibonacci sequence, where each term sums the two before it, shows up in patterns like sunflower spirals.

    Open this card ↗