Vocabulary and Grammar
Learn the difference between counting numbers and order numbers, how to build them, and the main spelling exceptions.
By the end of this page, students can use cardinal numbers for quantity and ordinal numbers for position, dates, order, floors, and rankings.
Core Difference
Use cardinal numbers to count quantity.
Use ordinal numbers to show order or position.
Construction
Most ordinal numbers add -th to the cardinal number. However, the first numbers and some spellings change.
| Cardinal | Pronunciation | Ordinal | Pronunciation | Note |
|---|---|---|---|---|
| one | /wun/ | first | /furst/ | Irregular. |
| two | /too/ | second | /SEK-und/ | Irregular. |
| three | /three/ | third | /third/ | Irregular spelling. |
| four | /for/ | fourth | /forth/ | Add -th. |
| five | /fiv/ | fifth | /fifth/ | ve changes to f. |
| eight | /ayt/ | eighth | /ayth/ | Only one t. |
| nine | /nain/ | ninth | /nainth/ | Drop the e. |
| twelve | /twelv/ | twelfth | /twelfth/ | ve changes to f. |
| twenty | /TWEN-tee/ | twentieth | /TWEN-tee-eth/ | y changes to ie + th. |
Compound Numbers
In compound numbers, only the last number decides the ordinal ending.
Common Uses
Say Unit 2, Lesson 3, and Page 10 with cardinal numbers. Say the second unit, the third lesson, and the tenth page with ordinal numbers.
Practice
I have three pencils.
Maria is third.
My birthday is on July 22nd.
This is my first English course.