Abacus finger method 9_4_1 is

Answer 1

a technique for using your fingers to perform computations on an abacus. In this particular method, the thumb and four fingers on each hand are assigned specific values: the thumb represents 5, and the four fingers represent 1 each. When using the abacus, you would place the number of beads representing each digit onto each finger, and then use them to perform computations. For example, if you wanted to add 349 and 256, you would use your fingers on each hand to represent those numbers, then add them up on the abacus by moving the appropriate beads.