Using numbers in Korean is very similar to Japanese and Chinese because those three use same Chinese numbers with different pronunciations. But this fact is applied for only cardinal numbers(one, two, three, …), not ordinal numbers (eg. first, second, third, …).

#### Basic Reading

Arabic | Cardinal | Ordinal prototype^{1} | Chinese cardinal |
---|---|---|---|

1 | 일[il] | 하나[hana] | ⼀ |

2 | 이[i] | 둘[dool] | ⼆ |

3 | 삼[sam] | 셋[set] | 三 |

4 | 사[sa] | 넷[net] | 四 |

5 | 오[o] | 다섯[daseot] | 五 |

6 | 육[yuk] | 여섯[yeoseot] | 六 |

7 | 칠[chil] | 일곱[ilgop] | 七 |

8 | 팔[pal] | 여덟[yeodeop] | 八 |

9 | 구[goo] | 아홉[ahop] | 九 |

10 | 십[sip] | 열[yeol] | 十 |

Actually, these ordinal numbers are not actually ordinal. They are original-Korean numbers, and used to make real ordinal numbers in some contexts. (So if you use this forms as it is, it’s not an ordinal number. To know how to use them, see the end of this post.)

English-like languages have *special* notations for 11 and 12, but Korean-like languages doesn’t have such exceptions.

11 | 십일 | 열하나 | 十一 | 첫 becomes 하나 if you use it after 10 or larger. |

12 | 십이 | 열둘 | 十二 | |

13 | 십삼 | 열셋 | 十三 | |

… (You can combine 십/열 and 1-digit numbers.) | ||||

20 | 이십 | 스물 | 二十 | |

21 | 이십일 | 스물하나 | 二十一 | |

30 | 삼십 | 서른 | 三十 | |

40 | 사십 | 마흔 | 四十 | |

50 | 오십 | 쉰 | 五十 | |

60 | 육십 | 예순 | 六十 | |

70 | 칠십 | 일흔 | 七十 | |

80 | 팔십 | 여든 | 八十 | |

90 | 구십 | 아흔 | 九十 | |

100 | 백[baek] | 百 | There is no more ordinal numbers from 100, so we use same names to cardinal numbers.^{2} | |

1000 | 천[cheon] | 千 | ||

1,0000 | 만[man] | 萬 | ||

1000,0000 | 억[eok] | 億 | ||

10^{12} | 조[jo] | 兆 | ||

10^{16} | 경[gyeong] | 京 | ||

0 | 영[yeong] | 零 | In middle digits of a number, we don’t say anything for 0, just like English. |

English puts a comma between every 3-digits because it uses ‘thousands’ scaling, but Korean puts it between every 4-digits because it uses ‘ten-thousands(만)’ scaling. However, 3-digits separation is more frequently used in the real life such as banks.

Some examples:

24 | 이십사 | 스물넷 | 二十四 |

101 | 백일 | 백하나 | 百一 |

135 | 백삼십오 | 백서른다섯 | 百三十五 |

2358 | 이천삼백오십팔 | 이천삼백쉰여덟 | 二千三百五十八 |

1,2345,6789 | 일억 이천삼백사십오만 육천칠백팔십구 | 一億 二千三百四十五萬 六千七百八十九 | |

You may notice there is one-to-one mapping with Chinese numerals and Korean numerals. |

If you use 1 in places of larger than 10000, we usually add a prefix ‘일’(1) to the number. So 1000,0001 is 일억일, not 억일, but 1,0000 is 만, not 일만. (You may use ‘일만’, but it’s only in some formal notations.)

It’s easy to think the last example as 1x10^{8} (일x억) + 2345x10^{4} (이천삼백사십오x만) + 6789x1 (육천칠백팔십구). If you want test yourself, there is a perl script that converts arabic numbers to Korean pronunciations. (Note that the script uses CP949 or EUC-KR encoding, not UTF-8. But I think if you copy & paste its source code in UTF-8 encoding, then it will run well in UTF-8 encoding.)

#### Floating numbers

To speak floating numbers, you can say ‘.’ as 점, and the following digits in 1-digit numbers, such as:

10.13579 = 십점일삼오칠구

365.2422 = 삼백육십오점이사이이

For more mathematical notations such as equations, fractions and squares, I will introduce them (maybe far-_-) later.

#### Using ordinal numbers

If you use ordinal numbers as the attributive forms, the last sounds in 2, 3, 4 and 20 are dropped. The affix ‘-째’ is something similar to ‘-th’ in English.

English | Korean | Desc. |
---|---|---|

first | 첫째, 첫번째 | ‘첫’ is another expression of ‘하나’ only used in ordinal numbers. |

second | 둘째, 두번째 | you may notice that the form is varied. |

third | 셋째, 세번째 | |

fourth | 넷째, 네번째 | |

fifth | 다섯째, 다섯번째 | |

sixth | 여섯째, 여섯번째 | |

seventh | 일곱째, 일곱번째 | |

eighth | 여덟째, 여덟번째 | |

ninth | 아홉째, 아홉번째 | |

tenth | 열째, 열번째 | |

eleventh | 열한번째 | |

twelfth | 열두번째 | |

thirteenth | 열셋째, 열세번째 | |

fourteenth | 열넷째, 열네번째 | |

… | … | |

twentieth | 스무번째 | Not 스물번째 |

… | … | |

thirtieth | 서른번째 |

and so on.

You can read an article about Korean numerals on Wikipedia instead of this.