It depends on the dialect of French in use.
Standard French (which is used in most French-speaking countries in the world) has the number as "quatre-vingts", which literally means "four-twenties".
In some dialects of Swiss French (but not in Geneva or Jura), the number is "huitante" or "ochante", which it literally "eight-ty".
In Acadian French, the number is "huit fois dix", which literally means "eight times ten".
quatre-vingt six
In French, eighty-six is said as "quatre-vingt-six."
quatre vingt un
quatre-vingt neuf
we say neuf-cent quatre-vingt-neuf
Quatre-vingt-quatre mille.
deux cent quatre-vingt-neuf
le club des plus de quatre-vingt.
To say a year in French, break it down and say each number individually. 1683 = Mille six cent quatre-vingt-trois (one thousand six hundred eighty-three)
Quatre vingt
Nineteen eighty in French is "mille neuf cent quatre-vingts."
"âgé(e) de quatre-vingt cinq ans"