Pythagorean Numerology

Pythagoras (attributed) · ~500 BC

Western numerology system that assigns numerical values to letters.

It assigns values from 1 to 9 to each letter of the alphabet. It's used to calculate Expression (and, combined with the date, Life Path and Personality). Its digit reduction is the mathematical equivalent of the remainder modulo 9.

Pythagorean numerology is the most widely used system in the West. Although it's attributed to Pythagoras, modern historians find no direct evidence. What is real is the underlying mathematical fact: since every number equals 9 · k plus a remainder, reducing a number to a single digit (adding its digits) is equivalent to calculating its remainder modulo 9. In other words, the traditional 'reduction' matches exactly the modular arithmetic of class 9, an operation mathematicians studied formally centuries later.