It's more of a mathematical problem than a lingual one.
Bear in mind that in western culture, the numbes system is "thousand based" while in Asia it's "ten thousand based"
In other words, we have one more unit after thousand (천) which is called 만
western number system:
base:
one
ten
hundred
thousand
extended:
million
billion
trillion
Asian number system
base:
일 (one)
십 (ten)
백 (hundred)
천 (thousand)
만
extended:
억
조 (trillion)
경
Let's take a very large number for example
2,492,478,623,911
2(two) trillion,
492(four hundred ninety two) billion,
478(four hundred seventy eight) million,
623(six hundred twenty three) thousand,
911(nine hundred and eleven)
In order to read this number in Korean, it's much easier when you put the commas every fourth digit
2,4924,7862,3911
2(이)조
4924(사천구백이십사)억
7862(칠천팔백육십이)만
3911(삼천구백십일)
Unfortunately, if will take quite a while until you get used to this difference.
We used to put commas every fourth digit until late 80s, but we adopted the western standard since then.
So you will have no problems writing the numbers with spaces or commas every third digit. (reading them is a different story)
And note that we have only one unit for currency (won) and no cents like in Euro or Dollar.
The last two digits must be an error therefore.