Numbers and Ordinals
Cardinals count; ordinals show order.
Examples
- three, third
- twenty, twentieth
Key rules
- Cardinals count: one, two, three
- Ordinals show order: first, second, third
- Most ordinals add -th: fourth, tenth; spellings change: five → fifth, twelve → twelfth, twenty → twentieth
- Use hyphens for 21-99: twenty-one
Common mistakes
- the three floor → the third floor
- I live on 5 floor → I live on the fifth floor
💡 Tip: Use ordinals for rank and dates, cardinals for amounts.