When it comes to spelling out numbers, knowing when and how to do so correctly might be trickier than you imagine. Many organizations and publications have their own style guides describing when and how to spell out numbers, but there are some general guidelines you can keep in mind when digits pop up in writing.

Typically, you should spell out numbers below 10. Numbers over 10 should be represented in numerals—e.g., 53— unless the number is at the beginning of the sentence. You should try to avoid starting a sentence with a number, but if it can’t be avoided, it should be spelled out. These are the two most important rules. Read on to learn more tricks for correctly spelling out numbers.

**How to spell 40: ***fourty* or *forty*?

*fourty*or

*forty*?

The number *four* and its various iterations follow an irregular pattern. For the number 14, it follows the general rule: 14 is spelled *fourteen* (*-teen* is a suffix denoting 10).

When it comes to the number 40, you would think it would be spelled *f ourty* (

*-ty*is the suffix denoting multiples of ten). However, the

*U*is dropped, meaning 40 is correctly spelled

*f*.

**or**ty**How to spell 15: ***fivteen* or *fifteen*?

*fivteen*or

*fifteen*?

The number *five* and its related numbers are also tricky. In most instances, the *V* turns into a second *F* and the final *E* is dropped. For example: 15 is spelled *f ifteen* (rather than

*fi*). 50 is spelled

**ve**teen*f*, not

**if**ty*f*.

**ive**tyFinally, the ordinal number 5th is spelled *fifth*. (The suffix *-th* denotes ordinal numbers.)

**How to spell 18:*** eightteen* or *eighteen*?

*eightteen*or

*eighteen*?

As we noted before,* -teen* is a suffix that denotes 10. When combined with* eight* to form the number 18, the final *T* in *eight* is dropped. The number 18 is correctly spelled *eigh teen*.

**How to spell 9th: ***nineth* or *ninth*?

*nineth*or

*ninth*?

The number *nine* drops the final *E* when combined with the suffix *-th* to form the ordinal number 9th, becoming *ninth*. However, this rule does not hold when combined with other suffixes: 19 is spelled *nin eteen* and 90 is spelled

*nin*.

**e**ty**How to spell 12th: ***twelveth* or *twelfth*?

*twelveth*or

*twelfth*?

Yes, we remember when we told you that the *V* at the end of five is turned into an *F* when combined with a suffix. But, for the number 12 (twelve), the rule is inverse; when combined with the suffix *-th* to form the ordinal number 12th, the word is spelled *twel fth*. The final

*V*is turned into an

*F*, and the final

*E*in

*twelve*is dropped.

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**When do you hyphenate numbers?**

When it comes to spelling out large numbers, it can be tempting to hyphenate everything. We get it. But you really only want to hyphenate compound numbers between 21 and 99. A compound number is any number that is a combination of more than one number, such as 52 or *fifty-two*.

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**When do you spell out years?**

The number of the year is typically written as a numeral, such as 2022. This is true even when the number is less than 10, like 6 CE. That said, if the year comes at the beginning of a sentence, you should write it out like other numbers. Like we do when saying the year aloud, it is typical to divide the first two digits and the second two digits into individual numbers. For example, the year 1982 would be written *nineteen eighty-two*. (Remember, we hyphenate compound numbers between 21 and 99.)

When it comes to years that end in 00, we represent this as *hundred*. So, the year 1200 would be written* twelve hundred*.

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**How to spell ½: ***one over two* or *one half*?

*one over two*or

*one half*?

Generally speaking, you want to represent fractions in digits when writing them out, as in 56/325. However, there are some important exceptions. First, when using common fractions such as ¼, ⅓, and ½, it is typical to write out the fraction. Remember, the numerator is expressed as a cardinal number and the denominator is expressed as an ordinal number. For example: ¼ would be written *one fourth*.

The biggest exception to these rules is ½, which is written *one half* and 2/2, which is written *two halves*.

What’s the difference between *mean*, *median*, and *mode*?

You may have noticed from the example of 2/2 that only the denominator is pluralized when the numerator is more than one, so ⅔ is written *two thirds*.

You do not need to include a hyphen when writing out a fraction but it is typical to do so when using it as an adjective attached to a noun, as in *The glass was two-thirds full*. You can include a hyphen or not when writing fractions, as long as you are consistent throughout the document.

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**When do you spell out decimals?**

Generally, you will not need to spell out decimals when writing. However, if you do, the decimal point (.) is expressed as “point” and the numbers on the right of the decimal are expressed as independent numbers. For example, 2.25 would be written out* two point two five*, rather than “two point twenty-five.” This is very informal and should otherwise be avoided. Using numerals is fine for decimals.

Numbers are trickier than the Count led you to believe on Sesame Street, right? Hopefully this little guide will make it easier to follow the many rules (and exceptions to the rules) required for writing out numbers. To test your new knowledge, you can take our spell-that-number quiz here. Or if you need one more study session, review with the help of our flashcards and this word list.