• 0750± positional notation
By the 8th
century, Indian mathematicians had perfected positional notation and over the next several centuries, Arab merchants, scholars and conquerors began to spread it into Europe.
-- vigesimal, Maghreb, Hebrew, glyph, Aztecs, duodecimal, sexigesimal
http://qindex.info/i.php?x=4984
○○○ 0850 ± ⪢⪢
During the 9th
century, Scandinavia in northern Europe is populated by, among others, the Vikings, excellent sailors who explore in all directions to plunder but also to develope trade routes.
http://qindex.info/i.php?x=5285