The ordinal number of 1- 100 can be divided into four categories. 1, the first (1st), the second (2nd) and the third (the third abbreviated form in brackets) are all composed of Arabic numerals followed by the last two letters of ordinal number, and so are the following categories. There are only three such ordinal numbers, which is quite special in the whole ordinal number. Just like the first cardinal word, you need to recite it one by one. 2. Category II: IV (4), IV (5), V (5), VI (6), VII (7), VIII (8), IX (9 10). Tenth Eleventh (1 1th) Eleventh Twelfth (12th) Twelfth Thirteenth (13th) Thirteenth Fourteenth (14th) Fourteenth Fifteenth (/kloc-) Fifteenth sixteenth (16) sixteenth seventeenth (17) seventeenth insight (18) eighteenth nineteenth (19) there are sixteen such ordinal numbers * *. They are all formed by adding the suffix -th after the corresponding cardinal words. Pay attention to the spelling of the fifth, eighth, ninth and twelfth words. 3. Category III: 20th (20), 30th (30), 30th, 40th (40), 40th, 50th, 60th (60), 60th, seventieth (70), seventieth, eightieth (80) and ninetieth (90). They are formed by changing Y in the suffix -ty of the corresponding ten-digit integer to I and adding the suffix-eth. 4. Category IV: Category XXXI (3 1), Category XXXI, Category Sixty-two (62), Category Sixty-two, Category VII (87), Category Eighty-seven, Category Ninety-eight (98) This category of ordinal numbers means "the first dozen", followed by "which dozen". In terms of composition methods, they all change from the cardinal number of "more than ten", and the ten digits remain unchanged. Just change the cardinal number in the unit to ordinal number.