Any tips / links on how to use our hands as "calculators"?

Question

I mean there are those who use their hands fingers, knuckles, and all to easily do multiplication or long additions. Any easy way to do it?

Answer 1

You might try Chisenbop. See the following on-line references:

http://www.cs.iupui.edu/~aharris/chis/chis.html
http://en.wikipedia.org/wiki/Chisenbop

Answer 2

Multiply by 9s:

Hold down the finger of the other multiplicand, then read the fingers as the tens and the ones

Ex, 8 times 9

Count from either pinkie to number 8, fold it down and you have 7 on one side and 2 on the other. Works for 1 through 9.

Also, years ago a read a book by Trachtenberg (unsure of the spelling). If I recall, a POW developed a system.