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How did the French end up with their 'crazy' numbers?

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How did the French end up with their 'crazy' numbers?
In French these petrol prices literally translate as 'the unleaded four-twenties-fifteen costs one euro and four-twenties-seventeen cents, while the unleaded four-twenties-eighteen costs one euro and four-twenties-ten cents'. (Photo by Sameer Al-DOUMY / AFP)

Once you get above 69 things get a little complicated in France - we look at how France ended up with its bizarre numbering system, and why it will never change.


When it comes to learning how to count in French you don't just need linguistic skills - you also need some maths skills to rapidly calculate that 'four twenties ten eight' is in fact 98.

Even the most proficient French speaker will relate to that all-too-familiar moment where you freeze as you jot down a phone number or have to scribble out few digits because what you thought was sixty-something turned out to be seventy two.

It might be smooth sailing until you get to sixty-nine, but then funny things start to happen because the French don't have a separate word for seventy, or eighty, or even ninety for that matter.

Other Francophone countries have simply made up a word for 70, 80 and 90, but in France it seems that people still prefer to cobble together their numbers by adding up smaller numbers. 


Take 77 for example, or rather, ‘sixty-ten-seven’ (soixante-dix-sept) as it would be said in French. And it gets worse. Ninety-nine translates to 'four-twenty-ten-nine' or quatre-vingt-dix-neuf - can you imagine the life of salesman trying to flog discount TVs for €99.99?

To make things more difficult, large numbers in French are generally spoken as a whole rather than broken down into digits. So a Peugeot 206 is 'two oh six' in English but deux cent six (two hundred and six) in French.

If you live in Val d'Oise (95) you will need to say quatre-vingt quinze for your département number, rather than cheating and saying neuf cinq (the exception to this rule is le neuf trois).

If you want to say that basic unleaded petrol now costs €1.97 per litre, you need to explain that "Le sans plomb quatre-vingt-quinze est un euro quatre-vingt-dix sept"

Phone numbers in France are said in pairs, so someone might tell you their number is zero six, trente-et-un, quatre-vingt-dix etc.

The Local's readers regularly show their frustration with French numbers.

"When the French say numbers to me my ears just shut down! It is denial I know," said one reader.

One reader said the system was "specially designed to puzzle foreigners”. 

Another reader admits that: “ Still after five years I have to stop and think about it”. 


Our troubles are made all the more frustrating given that in other French-speaking countries, the system follows a more logical pattern (logical to us, anyway).

Switzerland uses ‘septante' for 70, ‘octante’ or ‘huitante’ for 80 and ‘nonante’ for 90. In some parts of Belgium, some of these are used too. 

So why didn't the French think of this?

Historically, there is more than one method for counting. There is the method that us Anglophones know, which comes from the Romans and is called base ten. This means that everything is based on multiples of ten. 

In French too, we see this, up until the seventies when, as we've said, things go weird. Then in comes the "vigesimal system" which used the base 20, hence quatre-vingt (80).

This is supposedly as they used their feet as well as their hands to count. Fingers and toes included, you get twenty. 

Many believe it ended up in French due to the influence of the Celts in France, whose languages use the base 20 system. While others say it was the Viking influence and point to the fact that Danish numbers also works on the base 20 "vigesimal system".

One good example of this is the Paris hospital called l’Hôpital des Quinze-Vingts (The Hospital of fifteen-twenty). The hospital was so named because it housed 300 beds and 300 is 15 times 20. Perfectly logical when you put it like that.

But why then, didn’t they just stick to one?

READ ALSO: How to get the government to pay for your French classes

Well the story goes that when the Roman invaders came to France, they tried to impose their language and methods on the French but they weren’t entirely successful.

There was a short period during the Middle Ages when the roman versions ‘septante’, ‘huitante’ and ‘nonante’ looked like they were going to stick but then tradition partially prevailed for the French and they managed to reclaim their ancient ways of saying eighty (quatre-vingt) to ninety-nine (quatre-vingt-dix-neuf).

No doubt French learners would love it if the language guardians at the Academie Francaise decided to ditch the fingers and toes system and adopt the Swiss French number system, but we have to remember that most French people don't have an issue with their numbers.

Gilles Montrichard, from ABA English Academy said there was "no need to change something that causes no problems for French people". 

And criticise as we might, the idea of counting in twenties actually used to be part of the English language too. 

Think back to Abraham Lincoln’s famous Gettysburg address and you may remember how without realising, we know ‘score’ to mean twenty: “Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty…”

To translate, ‘Four score and seven’, means four-twenty and seven, in other words, 4 x 20 + 7 (87) -  on exactly the same principle as the French!


So maybe it isn’t such a crazy system after all.

After all, as another reader of The Local points out, the system is “great for children learning multiplication". So maybe there is an up side.

It seems that unfortunately it's just one of those things we are going to have to put up with in life.

By Hattie Ditton


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Christopher Ley-Wilson 2023/11/28 18:02
In the 20 formula, what happened to 40 (deus vingt, of course) and 60 (trois vingt)? And how about 30 and 50 while we're about it? I've a situation with saying part of my car reg number, namely "quartre vingt et un", or should I say "quartre cents vingt et un"? No problem really but what's the rule?
christopher hobday 2023/03/30 21:49
Three score years and ten ring any biblical bells? I am fairly used to the number system and thought I was was OK until I was asked for my date of birth (1945). I blurted "Dix neuve cent, quarante cinq". I think it should have been "Mille, neuve cent, quarante cinq" but le docteur understood me perfectly well. As I left I apologised for my poor French. In response he offered a reassuring smiling handshake, and "Pas grave monsieur."
Philip Pinnell 2023/03/23 07:29
so if it is a 20 based system why is it quarente and not deux-vingt?
Anonymous 2021/06/30 04:09
I teach my students to learn by heart: their date of birth. Their phone numbers and address, etc. They even learn their family members main info related to numbers: miracle o miracle most of them are good with French numbers now.
Anonymous 2020/07/14 22:44
At one time, during the many years I lived in Belgium, my telephone number was <br />010 22 76 97. (Sorry if somebody else has that number now.) If I'd been living in France, I would have refused it! But then I think of how easily we Brits don't hesitate between 18 and 80, 19 and 90, so no writing down 99 as 80+19. Enough to deny you French nationality! My French accountant was bemused when I made him slow down on long numbers until I pointed out that what was 99 to him was 4x20+10+9. He'd never thought of it like that.
Anonymous 2019/04/09 22:53
Excellent article! Quattre vingt dix neuf points!

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