Learning French: Système de numéro

So last week I finally get to count in French on my Doulingo account, not just one, two, three, but up to 100. And I met a bizarre counting system.

Counting in French is not similar to counting in English, Vietnamese, or Chinese language (the three that I have at least some knowledge of). That is enough to make this an odd ball I have never seen before.

4*20 + 19

How different?

English number system is this: twenty, thirty, forty, fifty, sixty, seventy, eighty…. , and then add one to nine for 21, 22,....(which is what I expected counting in French would be like, silly me).

French count their seventy as soixante-dix (sixty and ten) and eighty as quatre-vingts (four-twenties) and ninety as quatre-vingt-dix (four-twenties and ten). (See more below).

So it is a weird system. Make sense (mathematically) but, still, weird. So I did some digging into this type of counting system.

It is called Vigesimal numeral system, base 20 (the one used in English is decimal, base 10).

Why twenty? 
One source says it is because we human have total of 20 fingers and toes.

And French is not alone. Many European country have the same or similar system, also Maya and Aztec and some Asia region. 

Danish word for 55 femoghalvtreds "five more than half the third twenty-block" [1] – a mouthful and a lot of mental calculation. (I wonder if the word come naturally as children learn the language or would they grow up to be a little bit more efficient with simple math.)

For more interesting and in-depth information of numeral system, consult The Number Concept: Its origin andDevelopment by Levi L.Conant, free on Guntenbert.

A glimpse of French numbers:

Number	In French	literal
20	vingt	20
21	vingt-et-un	20 and 1
30	trente	30
40	quarante	40
50	cinquante	50
60	soixante	60
70	soixante-dix	60 + 10
71	soixante-et-onze	60 and 11
72	soixante-douze	60 + 12
73	soixante-treize	60 + 13
74	soixante-quatorze	60 + 14
75	soixante-quinze	60 + 15
76	soixante-seize	60 + 16
77	soixante-dix-sept	60 + 17
78	soixante-dix-huit	60 + 18
79	soixante-dix-neuf	60 + 19
80	quatre-vingts	4 × 20s
81	quatre-vingt-un	4 × 20 + 1
82	quatre-vingt-deux	4 × 20 + 2
90	quatre-vingt-dix	4 × 20 + 10
91	quatre-vingt-onze	4 × 20 + 11
92	quatre-vingt-douze	4 × 20 + 12