> I was taught basic counting, addition, and subtraction using a finger-abacus system called Chisanbop: https://en.wikipedia.org/wiki/Chisanbop https://en.wikip

> I was taught basic counting, addition, and subtraction using a finger-abacus system called Chisanbop: https://en.wikipedia.org/wiki/Chisanbop https://en.wikipedia.org/wiki/Chisanbop I was just taught counting using it, it was a quick bonus math class one day. It is super useful for counting things off without losing place. Even being able to go up to 10 on just one hand is useful.