Tham khảo
1 (one) → 1st (first)
2 (two) → 2nd (second)
3 (three) → 3rd (third)
4 (four) → 4th (fourth)
5 (five) → 5th (fifth)
6 (six) → 6th (sixth)
7 (seven) → 7th (seventh)
8 (eight) → 8th (eighth)
9 (nine) → 9th (ninth)
10 (ten) → 10th (tenth)
11 (eleven) → 11th (eleventh)
12 (twelve) → 12th (twelfth)
13 (thirteen) → 13th (thirteenth)
14 (fourteen) → 14th (fourteenth)
15 (fifteen) → 15th (fifteenth)
16 (sixteen) → 16th (sixteenth)
17 (seventeen) → 17th (seventeenth)
18 (eighteen) → 18th (eighteenth)
19 (nineteen) → 19th (nineteenth)
20 (twenty) → 20th (twentieth)
21 (twenty-one) → 21st (twenty-first)
22 (twenty-two) → 22nd (twenty-second)
23 (twenty-three) → 23rd (twenty-third)
24 (twenty-four) → 24th (twenty-fourth)
25 (twenty-five) → 25th (twenty-fifth)
26 (twenty-six) → 26th (twenty-sixth)
27 (twenty-seven) → 27th (twenty-seventh)
28 (twenty-eight) → 28th (twenty-eighth)
29 (twenty-nine) → 29th (twenty-ninth)
30 (thirty) → 30th (thirtieth)
31 (thirty-one) → 31st (thirty-first)