For more like this subscribe to the Open University channel https://www.youtube.com/channel/UCXsH4hSV_kEdAOsupMMm4Qw
Free learning from The Open University http://www.open.ac.uk/openlearn/science-maths-technology/mathematics-and-statistics
How South American Incas kept records by the use of knots.
(Part 4 of 7)
Playlist Link - http://www.youtube.com/playlist?list=PL18FC35BAE7676C38
Transcript link - http://media-podcast.open.ac.uk/feeds/mst121-sundials/transcript/mst121.02_track_5_00518_6459.pdf
For more information about Incas and their knots visit http://www3.open.ac.uk/study/undergraduate/course/mst121.htm