What Are Ordinal Numbers?

Ordinal numbers tell us the position or order of something in a sequence. When you know who came first in a race, which day of the month it is, or which floor to get off the elevator, you are using ordinal numbers.

Cardinal vs. Ordinal: "There are 3 apples" uses a cardinal number (how many). "She took the 3rd apple" uses an ordinal number (which position).

Ordinal Number Words and Abbreviations

1: first - 1st

2: second - 2nd

3: third - 3rd

4: fourth - 4th

5: fifth - 5th

6: sixth - 6th

7: seventh - 7th

8: eighth - 8th

9: ninth - 9th

10: tenth - 10th

11: eleventh - 11th

12: twelfth - 12th

20: twentieth - 20th

21: twenty-first - 21st

Spelling Rules for Ordinal Suffixes

Most ordinal numbers follow predictable rules:

Numbers ending in 1 → -st (1st, 21st, 31st) - except 11th
Numbers ending in 2 → -nd (2nd, 22nd) - except 12th
Numbers ending in 3 → -rd (3rd, 23rd) - except 13th
All other numbers → -th (4th, 5th, 11th, 12th, 13th, 20th)

Tricky ones: 11th, 12th, and 13th always use -th, even though 1, 2, and 3 normally use -st, -nd, and -rd.

Irregular Ordinal Words

The first three ordinal words do not follow the pattern of adding a suffix. They must be memorized:

1st = first (not "oneth")
2nd = second (not "twoth")
3rd = third (not "threeth")

Starting with 4th (fourth), the pattern becomes regular.

Where We Use Ordinal Numbers

Ordinal numbers appear throughout daily life:

Race results: She finished first; he came in third.
Calendar dates: School starts on the first of September; my birthday is the 14th.
Building floors: Take the elevator to the 5th floor.
Waiting in line: She was the second person to arrive.
Contests and rankings: The team earned second place at the competition.

Practice Activities

Line up 5–10 classroom objects and ask students to identify the first, third, and last item.
Write today's date using an ordinal number (e.g., "Today is the 6th of June").
Play a race game where students answer questions about position (Who is first? Who is fourth?).
Read a story about a race or sequence of events and have students retell it using ordinal words.
Create a months of the year chart and label each month with its ordinal number position.

Frequently Asked Questions

What is the difference between cardinal and ordinal numbers?

Cardinal numbers tell how many - 1, 2, 3. Ordinal numbers tell position - 1st, 2nd, 3rd. You use cardinal numbers to count; you use ordinal numbers to describe order or rank.

Why do we say first, second, and third instead of oneth, twoth, and threeth?

The words first, second, and third come from Old English and Latin roots. They are irregular forms that we simply memorize, just like irregular plural nouns (child/children).

When do we use ordinal numbers in everyday life?

We use ordinal numbers for race results (she finished first), calendar dates (June 6th), floors of a building (third floor), and order in a line (the second person in line).