Usually we don‘t use the “decimal point” to express the number in Chinese ,especially in large numbers. It usually be used only in the unit below “元” which is "角/分/毛"（a fractional unit of money in China (=1/10 of a yuan or 10 fen)）。 About decimal point:100=一百，106.4=一百 零 六块/元 四毛/角/分(use in daily speaking)or106.4元（which is usually said by the sounding calculator or in writing ） Consequently,the last one of each number above is the correct one And the word "百万/千万" is usually used to discribe the approximately account of money.For intance,“This vase is worth 6 million=这个花瓶值六百万in speaking 600万in writing” 10,000=一万 100，000=十万 1000,000=百万. It looks a little bit complicated cause the "," is easer to use in English number but not in Chinese(As a Chinese I am also confused when I am learning large English number.At last I think it would be much more easier if you don't use ","or just ignore it when you are translating big numers into Chinese) For example:1,000ignore the comma 1000=1千 10000=1万 10 0000=十万 100 0000=百万 While about the other detail I agree with Clair Fang's answer (Personally thinking his is more short&clear) (｡･∀･)ﾉﾞIf U still have confuse I am happy to help~