Solved cryptogram
In a room of twenty three people, the odds that two of them share a birthday are better than even.
Mathematics Facts, sourced to Wolfram MathWorld.
What it means
The number feels far too small until you notice what is being counted. Twenty three people make two hundred and fifty three possible pairs, and each pair is a chance for a match. The question is not whether someone shares your birthday, which needs a much bigger room, but whether any two of them share one. The same arithmetic governs how often hash values collide.
The claim comes from Wolfram MathWorld, and the page it comes from was read on 2026-08-27 to confirm it still says this.
This is not the kind of claim that goes out of date, which is why it was set as a puzzle rather than a fact with a shelf life.
Solve it yourself
This fact is a cryptogram here: 77 letters over 18 different ones, graded easy.
- SourceWolfram MathWorld
- CollectionMathematics Facts
- Difficultyeasy
- Length77 letters, 18 of them different
Nearby in the collection
The facts either side of this one.
- Wolfram MathWorldhard, 79 letters
- Wolfram MathWorldmedium, 74 letters
- Wolfram MathWorldmedium, 70 letters
- Wolfram MathWorldeasy, 71 letters
About as hard as this one
Scored closest to it by the model behind our guide to solving cryptograms.
- Wolfram MathWorldmedium, 77 letters
- Wolfram MathWorldmedium, 76 letters
- Wolfram MathWorldmedium, 75 letters
- Wolfram MathWorldmedium, 79 letters