Why French Numbers Are Crazy: How to Count from 70 to 99 Without Crying

The Math Problem Hidden in French

Learning to count in French is smooth sailing from 1 to 69. The numbers make sense, they follow a logical pattern, and you start feeling incredibly confident. But then you reach 70, and the French language suddenly decides to turn into a mental math test. Welcome to the infamous vigesimal (base-20) counting system!

The 70s: Sixty plus Ten

There is no single word for "seventy" in standard French. Instead, you have to do some light addition. You say "sixty-ten" (soixante-dix).

• To keep counting, you don't go back to one. You keep adding teen numbers to sixty!
• 71: soixante et onze (60 and 11)
• 75: soixante-quinze (60 + 15)
• 79: soixante-dix-neuf (60 + 19)

The 80s: Four Twenties

Just when you get used to adding ten, the 80s introduce multiplication. The word for 80 is quatre-vingts, which literally translates to "four twenties" (4 x 20 = 80). Historically, the Celts counted in twenties using their fingers and toes, and this habit survived in French!

• Notice that for exactly 80, "vingts" gets an "s". But as soon as you add another number, the "s" drops.
• 81: quatre-vingt-un (Four twenties one) - Note: no "et" is used here!
• 85: quatre-vingt-cinq (Four twenties five)

The 90s: Four Twenties Ten

The 90s combine everything you just learned into one giant math equation. You multiply 4 by 20, and then add the teen numbers on top. 90 is quatre-vingt-dix (4 x 20 + 10).

• 91: quatre-vingt-onze (Four twenties eleven)
• 97: quatre-vingt-dix-sept (Four twenties seventeen)
• 99: quatre-vingt-dix-neuf (Four twenties nineteen)

The Swiss and Belgian Secret Shortcut

If this math seems exhausting to you, you are not alone! French speakers in Switzerland and Belgium completely rejected this system centuries ago. They created normal, logical words for 70, 80, and 90.

• 70: Septante
• 80: Huitante (in Switzerland) or Octante
• 90: Nonante

While you cannot use these shortcut words in Paris without sounding like a tourist, they are perfectly valid and official in the Francophone countries that border France. For the rest of us, it is time to brush up on our multiplication tables!

Want to build exam-ready vocabulary around this topic? Check out our TCF vocabulary lists.