This counting method, which uses the thumb as a pointer to positions on each finger, produces the number 12 as base for a number system (the duodecimal system).
A variant of this system was in use into the 20th century at markets of the Middle East, where all transactions invariably involve bargaining. Hidden under a cloth or other clothing, seller and buyer touch each other's fingers to indicate the price until agreement is reached. Through this method the seller does not reveal the agreed price to bystanders, and the next customer has no precedent to go on for the bargaining procedure.