Ironically, French tend to be good at math (they told me so when I was over there). Zero through 69 uses forms similar to counting in English (inferior to Chinese per the OP), and then it goes all wonky. 70 is sixty-ten, 71 is sixty-eleven,... but then 80 is four-twenty, and then 90 is four-twenty-ten, -eleven,... Ouch!
The rational is that they get very good at adding, multiplying, and then simplifying funky numbers in their heads (e.g. 73 + 92 would be sixty-eleven + four-twenty-twelve = hundred-sixty-five). Or maybe they get really good at memorizing addition tables, which would enhance their memorization skills. Or maybe they were just bragging over beer (good beer, excellent wine, très bon food ;-).
The rational is that they get very good at adding, multiplying, and then simplifying funky numbers in their heads (e.g. 73 + 92 would be sixty-eleven + four-twenty-twelve = hundred-sixty-five). Or maybe they get really good at memorizing addition tables, which would enhance their memorization skills. Or maybe they were just bragging over beer (good beer, excellent wine, très bon food ;-).
Ref:
http://french.about.com/od/vocabulary/ss/numbers_3.htm
http://french.about.com/od/vocabulary/ss/numbers_4.htm