In the Hindu-Arabic numeral system, large numbers are grouped into digits of three. For instance, one million is expressed as 1,000,000. It's not a surprise, then, that in English, you names of numbers that have groups of three digits. For instance, you have thousand for 1,000, million for 1,000,000, billion for 1,000,000,000, and so on.
Koreans use the Hindu-Arabic numeral system. They have a name for ten ("ship" in Korean), a name for hundred (bhek), and a name for thousand (chun). So far, so good. Here's where I get fucked up. Koreans have a name for ten thousand (mahn). From there, the give names to large numbers in a manner similar to English. Hundred thousand is "ship mahn" (ten + ten thousand). Million is "bhek mahn" (hundred + ten thousand). Ten million is "chun mahn" (thousand + ten thousand). From here Koreans introduce a new word for hundred million: "uhk." Then they do the same for numbers that are larger by orders of ten (ship uhk, bhek uhk, and so forth). You see now how this shit can get confusing when you're trying to translate quickly from English to Korean. That extra zero messes everything up.
So why do Koreans have a name for ten thousand? Did they use a different numeral system when they made these names?