Cardinal numbers (1–20)
| Number | Word | Number | Word |
|---|---|---|---|
| 1 | one | 11 | eleven |
| 2 | two | 12 | twelve |
| 3 | three | 13 | thirteen |
| 4 | four | 14 | fourteen |
| 5 | five | 15 | fifteen |
| 6 | six | 16 | sixteen |
| 7 | seven | 17 | seventeen |
| 8 | eight | 18 | eighteen |
| 9 | nine | 19 | nineteen |
| 10 | ten | 20 | twenty |
Tens (20–100)
| Number | Word |
|---|---|
| 20 | twenty |
| 30 | thirty |
| 40 | forty |
| 50 | fifty |
| 60 | sixty |
| 70 | seventy |
| 80 | eighty |
| 90 | ninety |
| 100 | one hundred |
For numbers in between, use a hyphen: twenty-one (21), forty-five (45), ninety-nine (99).
Hundreds and thousands
| Number | Word |
|---|---|
| 100 | one hundred |
| 200 | two hundred |
| 1,000 | one thousand |
| 10,000 | ten thousand |
| 100,000 | one hundred thousand |
| 1,000,000 | one million |
Ordinal numbers
Ordinal numbers tell position or order (first, second, third…).
| Number | Ordinal | Abbreviation |
|---|---|---|
| 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 |
| 20 | twentieth | 20th |
| 21 | twenty-first | 21st |
| 100 | hundredth | 100th |
Most ordinals are formed by adding -th: six → sixth, ten → tenth. Exceptions: first, second, third, fifth, eighth, ninth, twelfth.
Real world: addresses and floors
Ordinals appear constantly in daily life: "I live on the third floor." "Turn left at the second junction." "This is the fifteenth edition of the book." — knowing ordinals helps with addresses, instructions, and rankings.
Real world: dates
Dates in English use ordinal numbers: "My birthday is on the twenty-third of July." "The match is on Saturday the 5th." Written as 23rd July or July 23rd — both are common in UK and US English respectively.
Practice Problems
Write out in words: 47
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Write out in words: 305
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What is the ordinal form of 3?
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What is the ordinal form of 21?