Multiple choice general knowledge science & technology Numbers were recorded by knotting strings called quipu by - Mayan Civilization Indus Valley Civilization Babylonians Inca Civilization Reveal answer Fill a bubble to check yourself D Correct answer Explanation The Inca Civilization used quipu - a system of knotted strings - for recording numbers and keeping records. This was their primary method of numerical record-keeping since they did not have a written language.