The word Yupana derived from Quechua yupay (count) and is commonly defined as an abacus that was used to perform arithmetic operations and dates back to the time of the Incas.Now this has a mobile version on Android with which you can learn (In development, for now only the sum) how to use a Yupana.Sum:- At the beginning just click on the boxes to add the balls.- To operate press a couple of boxes (It can be twice the same box) that are in the same column to add the numbers and make the sum in each column is less than 10.- Read the result
Yupana: El ábaco Inca
