英語上數詞分為兩大類：基數詞和序數詞.
基數詞是表示數目的詞稱為基數詞,（1）．從1——10 one,two,three,four,five,six,seven,eight,nine,ten． （2）．從 11——19 eleven,twelve,thirteen,fourteen,fifteen,sixteen,seventeen,eighteen,nineteen．
序數詞是表順序的,1）從第一至第十九：one— first two— second/next three— third four-fourth five— fifth six— sixth seven— seventh eight—eighth nine—ninth ten— tenth eleven— eleventh twelve— twelfth thirteen —thirteenth fourteen—fourteenth fifteen—fifteenth sixteen—sixteenth seventeen—seventeenth eighteen—eighteenth nineteen—nineteenth 大多的序數詞都是由其相對應的基數詞后面添加“th”構成.（2）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ie,再加“th”構成.twenty——twentieth thirty——thirtieth