(n.) A contrivance employed by the ancient Peruvians, Mexicans, etc., as a substitute for writing and figures, consisting of a main cord, from which hung at certain distances smaller cords of various colors, each having a special meaning, as silver, gold, corn, soldiers. etc. Single, double, and triple knots were tied in the smaller cords, representing definite numbers. It was chiefly used for arithmetical purposes, and to register important facts and events.

Comptometer abacus adding analog computer arithmograph arithmometer calculating machine calculator cash register computation counter difference engine digital computer electronic computer listing machine pari-mutuel machine quipu rule slide rule sliding scale suan pan tabulator