You must’ve been learning the Belgian version, because French numbers in France are kind of a mess.
Like English there are special words for some of the “teens” numbers, which is the least of the troubles. Compare deux (two) and douze (twelve) to huit (eight) and dix-huit (ten-eight, or eighteen). Mildly annoying, but we have special cases for “eleven” and “twelve” in English too, no big deal.
Then some of the tens are weird too. While quatre (four) and quarante (forty) are clear, six (six) and soixante (sixty) are a bit tricky, while deux (two) and vingt (twenty) don’t seem to be related. These are then combined in uneven ways, with twenty one being “vingt et un” (twenty and one), while other numbers using the hyphenated form of vingt-cinq (twenty-five). Again, annoying, but manageable.
And then there are the extra special case numbers like seventy, which in France is apparently soixante-dix, or literally “sixty ten”. In some countries this is a much more reasonable “septante”, but not in France. The French actually count their seventies like “soixante-dix-sept”, which translates into “sixty seventeen”, or seventy seven in English.
And then there’s eighty. Holy crap, the number eighty. In French eighty is apparently “quatre-vingts”, or “four twenties”. Whoever came up with that was a brilliant sadist. Requiring some basic multiplication just to count to eighty is downright evil stuff, especially for young kids. Ditto for whoever made ninety “quatre-vingts-dix” (four twenties ten).
Note: I am not a native French speaker; I’m just learning.