Today I’ve heard a talk about division rules. The lecturer stated that base 12 has a lot of division rules and was therefore commonly used in trade.

English and German name their numbers like they count (with 11 and 12 as exception), but not French:

`# | English | German | French ----------------------------------------------- 0 | zero | null | zero 1 | one | eins | un 2 | two | zwei | deux 3 | three | drei | trois 4 | four | vier | quatre 5 | five | fünf | cinq 6 | six | sechs | six 7 | seven | sieben | sept 8 | eight | acht | huit 9 | nine | neun | neuf 10 | ten | zehn | dix 11 | eleven | elf | onze 12 | twelve | zwölf | douze 13 | thir|teen | drei|zehn | treize 14 | four|teen | vier|zehn | quatorze 15 | fif|teen | fünf|zehn | quinze 16 | six|teen | sech|zehn | seize 17 |seven|teen | sieb|zehn | dix-sept 18 and 19 are "regular" 20 | twenty | zwanzig | vingt 21 |twenty-one | ein|und|zwanzig | vingt et un 22 |twenty-two | zwei|und|zwanzig | vingt-deux 23 - 69 are "regular" 70 | seven|ty | sieb|zig | soixante-dix = 60 + 10 .... 80 | eigh|ty | acht|zig | quatre-vingts = 4*20 ?!?! 81 |eighty-one | ein|und|achtzig | quatre-vingt-un = 4*20 + 1 ...`

So my question is:

Why do French count so strangely after 79?

(Are there other languages that count similar? What’s the historic / mathematical reason for this system?)

## Related Questions

**Answer**

Many languages have (at least relicts of) non-decimal counting, very often vigesimal (because we have 20 fingers plus toes), but also many other systems. I recommend an old Gutenberg project of mine, The Number Concept

Note for example that the Danish word for 55 is *femoghalvtreds* “five more than half the third twenty-block”

**Attribution***Source : Link , Question Author : Martin Thoma , Answer Author : Hagen von Eitzen*