1st - first
2nd - second
3rd - third
4th – fourth
5th - fifth
6th - sixth
7th - seventh
8th- eighth
9th – ninth
10th - tenth
11th- eleventh
12th- twelfth
13th – thirteenth
14th – fourteenth
15th – fifteenth
16th- sixteenth
17th- seventeenth
18th- eighteenth
19th- nineteenth
A partir do twentieth (vigésimo), os números ordinais das dezenas recebem a terminação –ieth. Para os números entre elas, as dezenas permanecem na forma de número cardinal (como 1, 2 e 3), e são as unidades que entram na forma ordinal. O vigésimo terceiro é twenty-third (23rd), por exemplo.
20th – twentieth
21rst – Twenty-first
22nd - Twenty-second
23rd - Twenty-third
24th - Twenty-fourth
25th Twenty-fifth
26th -Twenty-sixth
27th -Twenty-seventh
28th -Twenty-eight
29th-Twenty-ninth
30th – thirtieth
40th – fourtieth
50th – fiftieth
60th – sixtieth
70th – seventieth
80th - eightieth
90th - ninetieth
A partir do centésimo (100º), a regra para formar os números ordinais é colocar apenas o último número na forma ordinal. Por exemplo: centésimo quadragésimo (140º) é one hundred fourtieth (140th), e quingentésimo vigésimo oitavo (528º) é five hundred twenty-eighth (528th). A partir do milésimo (thousandth), milionésimo (millionth), bilionésimo (billionth) e assim por diante, vale a mesma regra.
100 – One/a hundred
1000 – One/a thousand
1000000 – One/a million
1000000000 – One/a billion
100th – One hundredth
1000th – One thousandth
1000000th – One millionth
1000000000th – One billionth
