# Interesting ‘Laws’

## Goodhart’s law

## Peter’s Principle

## Friedman Number …

Named after Stetson University mathematician Erich Friedman, is a number that can be calculated using its own digits, such as 736 = 36 + 7 or 3281 = (38 + 1) / 2.

A “nice” Friedman number is one in which the digits are used in order, such as 3685 = (36 + 8) × 5 or 3972 = 3 + (9 × 7)2.