Answer: quipu

AnswerCrossword Clue
QUIPUOld Peruvian calculating device
QUIPUQuechuan calculator
quipudevice consisting of a cord with knotted strings of various colors attached, used by the ancient Peruvians for recording events, keeping accounts, etc.
quipua device made of a main cord with smaller varicolored cords attached and knotted and used by the ancient Peruvians (as for calculating)
quipua device to help memory, also QUIPO, QUIPPU