It's kind of amazing how thorough this particular area of reconstruction is: https://en.wikipedia.org/wiki/Proto-Indo-European_numerals https://en.wikipedia.org

It's kind of amazing how thorough this particular area of reconstruction is: https://en.wikipedia.org/wiki/Proto-Indo-European_numerals https://en.wikipedia.org/wiki/Proto-Indo-European_numerals (and the continued astonishment I get at Indo-European languages being native from Iceland all the way to India and Siberia -- maybe I should say "from Iceland to Ireland, Italy to Iran and India")