Using an Abacus/Subtraction

Subtraction
Subtraction is the second most basic function of the abacus. The subract, the user displays the original number and takes away the desired amount of beads from the original number.

Example: (12-4) 12=12 000-0|-0 (1) 00-00|-0  (2) 12-4=8 0000-|-0  (0) 0-000|0-  (8)