The very earliest counting devices were human hands, with the fingers used as digits. There were limitations to this device, though, especially since each hand has only five fingers. To count more items, some cultures assigned even larger counts to other parts of the body. Such counting methods became tedious, so merchants and others who needed to keep track of assorted items turned to nature, using sticks, stones, and bones to count.

Eventually, devices called counting boards were developed. At first, the counting “boards” were simple, usually entailing drawing lines with fingers or a stylus in the sand or dirt. After all, merchants at outdoor markets needed to count items and calculate the cost of the goods in order to sell, and there was always plenty of sand and dirt at hand.

Portable boards made of wood, stone, or metal soon became more popular, with carved (or even painted) grooves or lines indicating units. These counting boards soon became more sophisticated, with beads, pebbles, or metal discs moved between the grooves or lines, allowing for an even larger number of items to be counted. Over even more time, they grew into what is called an abacus, a device with a frame holding rods with free-moving beads attached.