Solved cryptogram
Primes get rarer as numbers grow, and the rate at which they thin out follows a simple law.
Mathematics Facts, sourced to Wolfram MathWorld.
What it means
Near a number of a given size, the chance that it is prime is roughly one over its natural logarithm. That means about one in five numbers near a hundred is prime, and about one in a thousand near a number with four hundred digits. The result was guessed by Gauss as a teenager from tables of primes and not proved for another century.
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This is not the kind of claim that goes out of date, which is why it was set as a puzzle rather than a fact with a shelf life.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: 72 letters over 20 different ones, graded medium.
- SourceWolfram MathWorld
- CollectionMathematics Facts
- Difficultymedium
- Length72 letters, 20 of them different
Nearby in the collection
The facts either side of this one.
- Wolfram MathWorldmedium, 77 letters
- Wolfram MathWorldhard, 75 letters
- Wolfram MathWorldhard, 65 letters
- Wolfram MathWorldmedium, 75 letters
About as hard as this one
Scored closest to it by the model behind our guide to solving cryptograms.
- Wolfram MathWorldmedium, 81 letters
- Wolfram MathWorldmedium, 79 letters
- Wolfram MathWorldhard, 79 letters
- Wolfram MathWorldmedium, 70 letters