This is a method I am using for the last few years. It never ever came to my mind that that there may be a similar method exists. Did a google and found the word Chisanbop. Never ever got an empty page while searching for anything at instructablebles. Looked for chisanbop here and found nothing. So here it goes.

Chisanbop
Uses an abacus like finger counting method used to perform basic mathematical operations.
this method you can use your hands to count add/subtract till 99
No extra things are required.

Its funny how a single rod of abacus has 5 beads (4 earth beads and 1 sky bead), same as with hand! 4 fingers and 1 thumb.

Step 1: Units Place

Your right hand is the units place holder, as you will be writing units place on the right. You can count from 0 to 9 just by using one hand. See the images about how you will represent the digits.

Step 2: Tens Place

Your left hand is the tenss place holder, as you will be writing tens place on the left. You can count from 0 to 9 just by using one hand. Just by saying 10, 20, 30 instead of 1, 2, 3. See the images about how you will represent the digits.

Step 3: Examples How to Count

Now you are ready to count. Use both the hands.
Take the units place value and represent on the right hand.
Take the tens place value and represent on the left hand.

It can be easily seen that one can count till 99 using both hands.

Link: http://en.wikipedia.org/wiki/Chisanbop