Number times Recurring Part of Reciprocal gives 9-Repdigit/Mistake/First Edition

Source Work

 * The Dictionary
 * $142,857$
 * $142,857$

Mistake

 * This is a property of all the periods of repeating decimals. If the period of $n$ is multiplied by $n$, the result is as many $9$s as there are digits in $n$.

Correction
This should read:
 * This is a property of all the periods of reciprocals of (strictly) positive integers. If the period of $1/n$ is multiplied by $n$, the result is as many $9$s as there are digits in the period of $1/n$.

In of $1997$, this has been partially corrected to:
 * This is a property of all the periods of repeating decimals. If the period of $n$ is multiplied by $n$, the result is as many $9$s as there are digits in the period of $1/n$.