The abacus was developed in ancient Greece and Rome around 5000 BC – starting out at a slab with lines and beads, the placement of which would indicate quantities and track calculations. This is a step forward from slabs marked with clay tokens in the abstraction of quantities, the ease of performing calculations, and in the formal convenience of repeated use.
Eventually, the abacus evolved to the prototypical version we think of today (a frame with moveable beads) to meet the needs of people who don’t want their beads spilling all over the floor all the time, like travelling merchants.
As use of the abacus spread, different regions developed it in different ways, stalling out around the advent of numerals, of course. But, abaci are still in use today, improving mental math abilities and breaking reliance on electronic assistance.
Thanks, abacus! We appreciate you.