Number reduction

This is the process of finding a "base number" for a number by adding it's digits together. This process can be repeated until a single digit is gained. Numbers which reduce to the same digit are considered to have a connection of some kind (depending on the system).

Example
553 -> 5+5+3 = 13 -> 1+3 = 4

31 -> 3+1 = 4

Uses
This is one of the most basic operations of numerology and is used in nearly every known system. There are many ways to find meaning in numbers, the following are only examples.


 * Birth dates and other important life dates are reduced to one or two digit numbers; this number is supposed to say something about the personality and/or fate of the person
 * Dates of important life events are anaalysed the same way in order to determine their meaning for a person
 * Life events such as weddings are held at numerologically good days to attract luck
 * birth dates and other important life dates are reduced to a number under 22 to find out which tarot card corresponds to them; there are different oppinions about what those cards really mean for someones life then
 * values are ascribed to letters (there are many systems for doing this), then the name of a person is analyzed in the same way as the birth date, for the same purposes; this is called Gematria
 * random words are analyzed in the same way; words that add up to the same number are believed to possess an esotheric connection

Comments
An interesting side effect is that numbers which are the reverse of each other (eg. 123 and 321) always reduce to the same number. The same is true for numbers which contain the same ciphers, but in a completely different order.

If you divide a number by 9 using long division, the remainder is the same number as the one you'd obtain by reducing it to a single digit (if you replace a remainder of 0 with 9).

A mathematical curiosity
If you look at the list of numbers below 1000 that reduce to certain numbers, you will find the following strange phenomenon:


 * the numbers that reduce to 19 contain all ciphers
 * the numbers that reduce to 20 contain the ciphers 2 - 9
 * the numbers that reduce to 21 contain the ciphers 3 - 9
 * and so on, up to 27; the only number below 1000 that reduces to 27 is 999

Resources
All the Number pages in this wiki up to 1000 list what that number reduces to.

The number pages up to 27 have a list of numbers whicih reduce to that number: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27.