Ordinal numbers to 100th
key notes:
Cardinal numbers :
Cardinal numbers are numbers that represent the quantity of things or entities. They answer the question “how many?” or “how much?”
Cardinal numbers tell how many.
.
- Counting numbers like one (1), two (2), and three (3) are cardinal numbers.
Ordinal numbers:
indicate the position or order of items in a sequence. They tell us “which one” in a series or rank.
Ordinal numbers tell position
.
- Position numbers like first (1st), second (2nd), and third (3rd) are ordinal numbers.
| first | 1st |
| second | 2nd |
| third | 3rd |
| fourth | 4th |
| fifth | 5th |
| sixth | 6th |
| seventh | 7th |
| eighth | 8th |
| ninth | 9th |
| tenth | 10th |
| eleventh | 11th |
| twelfth | 12th |
| thirteenth | 13th |
| fourteenth | 14th |
| fifteenth | 15th |
| sixteenth | 16th |
| seventeenth | 17th |
| eighteenth | 18th |
| nineteenth | 19th |
| twentieth | 20th |
| twenty-first | 21st |
| twenty-second | 22nd |
| twenty-third | 23rd |
| twenty-fourth | 24th |
| thirtieth | 30th |
| thirty-first | 31st |
| fortieth | 40th |
| fiftieth | 50th |
| sixtieth | 60th |
| seventieth | 70th |
| eightieth | 80th |
| ninetieth | 90th |
| hundredth | 100th |
Learn with an example
▶️ Which of the following are ordinal numbers?
(There may be more than one.)
- fifty-seventh
- 17th
- 18th
- 90th
- These are all ordinal numbers:
- fifty-seventh
17th
18th
90th
▶️ Which of the following are ordinal numbers?
(There may be more than one.)
- eighty-one
- twenty-eight
- 3
- seventy-eighth
- This is an ordinal number:
- seventy-eighth
These are not ordinal numbers. These are cardinal numbers: - eighty-one
twenty-eight
3
▶️ Which of the following are ordinal numbers?
(There may be more than one.)
- forty-eight
- tenth
- 70th
- ninety-six
- These are ordinal numbers:
- tenth
70th - These are not ordinal numbers. These are cardinal numbers:
- forty-eight
ninety-six
Let’s practice!
