基數詞 序數詞one first / 1sttwo second / 2ndthree third / 3rdfour fourth / 4thfive fifth/ 5thsix sixth / 6thseven seventh / 7theight eighth/ 8thnine ninth / 9 thten tenth / 10theleven eleventh / 11thtwelve twelfth / 12ththirteen thirteenth / 13thfourteen fourteenth/ 14thfifteen fifteenth / 15thsixteen sixteenth / 16thseventeen seventeenth / 17theighteen eighteenth/ 18thnineteen nineteenth / 19twenty twentieth/ 20thtwenty- one twenty-first / 21sttwenty- two twenty- second/ 22ndtwenty-three twenty- third / 23rdtwenty-four twenty-fourth /24thtwenty-five twenty-fifth / 25thtwenty- six twenty-sixth/ 26thtwenty-seven twenty-seventh /27thtwenty-eight twenty-eighth /28thtwenty-nine twenty-ninth / 29ththirty thirtieth / 30th

擴充套件資料：

1~99的序數詞：表示順序的詞稱為序數詞。

一、從第一至第十九

其中，one— first， two— second， three— third， five— fifth，eight—eighth，nine—ninth，twelve— twelfth為特殊形式，其它的序數詞都是由其相對應的基數詞後面新增“th”構成。例如： six— sixth、nineteen— nineteenth．

二、從第二十至第九十九

整數第幾十的形式由其對應的基數詞改變結尾字母y為i，再加“eth”構成。twenty——twentieth thirty——thirtieth

三、表示第幾十幾時，用幾十的基數詞形式加上連字元“－”和個位序數詞形式一起表示。