•Present Perfect
Scientists say they have found evidence of a giant planet in the solar system. There have only been two true planets discovered since ancient times. Planets have been predicted before and then were not found.
http://qindex.info/i.php?x=4149
•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