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# More number tricks.

Bikerman
The Sisyphus string - 123
Here, all numbers are attracted to 123.
Start with any string of digits. Write down the number of even digits, odds digits, and total digits to form a new number. Repeat this process until a stable value is attained.

Example
9,375,250. This contains two even digits, five odd digits, seven digits in total. This gives us a new number 257. 257 contains one even digit, two even digits, and three digits in total. This gives us a new stable number, 123.

The words to numbers attractor – 4
This is a similar example, but this time we use words.
Write down any number in words. Count the number of characters and write this down in words. Repeat until you arrive at a stable value.

Example
357. Written as Three hundred and fifty-seven. (We will count all spaces or hyphens as characters). This gives us 27 characters.
Twenty Seven gives us 12 characters.
Twelve gives us 6 characters.
Six gives us 3 characters.
Three gives us 5 characters.
Five gives us 4 characters.
Four gives us 4 characters and is stable.
Here's an easy one..

Take the last 2 digits of the year you were born.
Add them to the age you'll be at the end of the year.
Subtract the last 2 digits of the current year.
And if by some chance your answer is 200, you were born in the 1800's which is far more incredible than any trick I know

kelseymh
 onebadpenny wrote: Here's an easy one.. Take the last 2 digits of the year you were born. Add them to the age you'll be at the end of the year. Subtract the last 2 digits of the current year. Is your answer 100? You were born in the 20th century Is your answer 0? You were born in the 21st Is your answer something else? You aren't from around here are you?

Try this trick Jiroemon Kimura (born 19 April 1897). He's from around here, but you're making assumptions that aren't always valid.
dev2avi
With this trick,
you will be able to multiply any two numbers from 11 to 19 in your head quickly, without the use of a calculator.
I will assume that you know your multiplication table reasonably well up to 10x10.

Try this:
Take 15 x 13 for an example.
Always place the larger number of the two on top in your mind.
Then draw the shape of Africa mentally so it covers the 15 and the 3 from the 13 below. Those covered numbers are all you need.
First add 15 + 3 = 18
Add a zero behind it (multiply by 10) to get 180.
Multiply the covered lower 3 x the single digit above it the "5" (3x5= 15)
Add 180 + 15 = 195.