21用英语怎么写

How to Write 21 in English

If you're learning English, you might be wondering how to write the number 21. In this article, we'll guide you through the process of spelling out and writing 21 in English.

Spelling out 21

The number 21 can be spelled out in two ways: "twenty-one" or "twenty one". Both versions are considered correct. However, the most common way to spell out 21 is with a hyphen between the digits.

Writing 21 in Numerals

In addition to spelling out 21, you can also write it in numerals. Simply write the digits "2" and "1" next to each other, without any spaces or hyphens.

Other Facts about 21

21 is a number with many interesting mathematical properties. It is a composite number, which means it can be divided by other numbers besides 1 and itself. It is also the sum of the first six natural numbers (1 2 3 4 5 6 = 21).

In popular culture, 21 is often associated with the coming of age. In the United States, it is the legal drinking age. In many countries, it is the age at which a person is considered an adult and gains the right to vote.

Conclusion

In conclusion, writing 21 in English is a straightforward process. You can spell it out as "twenty-one" or "twenty one", and write it as "21" in numerals. With its interesting mathematical properties and cultural significance, 21 is a unique and important number.