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Writing Numbers as Words

This topic teaches how to write numbers as words, moving from single digits through teen numbers to two-digit numbers built from tens and ones. It covers the special number-word patterns learners must memorize, how tens and ones combine to make words like forty-seven, and common mistakes to avoid.

What Does It Mean to Write a Number as Words

Every number can be shown in two ways: as digits, like 7, or as words, like seven. Writing numbers as words means spelling out the name of a number instead of using digits. This skill helps you read number sentences, label pictures, and check that you really understand what a number represents, rather than just recognizing its shape.

Before working through this topic, it helps to be comfortable counting and spotting numbers in order, which you can review in number sequences with 1, 2, 3, 5, 10.

Number Words from One to Twelve

The words for the numbers one through twelve do not follow a pattern, so they simply need to be learned by heart. Here are the first ten as an example.

Digits 1 through 10 with their matching word names.

Eleven and twelve continue this pattern of unique words: 11 is eleven, and 12 is twelve. From 13 onward, a new pattern starts, which makes the words easier to build.

The Teen Pattern: 13 to 19

Numbers from thirteen through nineteen almost all end in the sound "teen," which is a helpful clue when reading or writing them.

13 is thirteen
14 is fourteen
15 is fifteen
16 is sixteen
17 is seventeen
18 is eighteen
19 is nineteen

Notice that thirteen and fifteen change their spelling slightly from three and five, so these two are worth extra attention when practicing.

The Tens Pattern: 20, 30, 40, and Beyond

Once you reach 20, numbers are grouped by tens. Each multiple of ten has its own word.

20 is twenty
30 is thirty
40 is forty
50 is fifty
60 is sixty
70 is seventy
80 is eighty
90 is ninety
100 is one hundred

Practicing with a hundred grid makes these tens words easier to remember, since each new row usually starts a new tens word. You can build this connection further with counting values in a number grid up to 100.

Combining Tens and Ones: Numbers Like 47

Any two-digit number that is not an exact multiple of ten is written by joining the tens word and the ones word with a hyphen. Thinking about place value helps here: the number 47 has 4 tens and 7 ones.

4 tens is forty, and 7 ones is seven, so 47 is written as forty-seven. In the same way, 62 is sixty-two, and 89 is eighty-nine.

This hyphen rule applies to every two-digit number from 21 to 99, except the exact tens, which never take a hyphen because they are already a single word (for example, 30 is simply thirty, not thirty-zero).

Reading number grids carefully also helps you spot when a value is missing, which connects to missing values in a number grid up to 100.

Worked Example

Write the number 53 as words.

Step 1: Break 53 into tens and ones. It has 5 tens and 3 ones.

Step 2: Write the tens word. 5 tens is fifty.

Step 3: Write the ones word. 3 ones is three.

Step 4: Join them with a hyphen. 53 is fifty-three.

Common Mistakes to Avoid

Mixing up thirteen (13) with thirty (30), since both start with "thir".
Mixing up fifteen (15) with fifty (50), since both start with "fif".
Forgetting the hyphen in two-digit words, such as writing "forty seven" as two separate words instead of forty-seven.
Writing "thirty-zero" instead of the correct single word thirty for a number like 30.

Why This Skill Matters

Writing numbers as words builds a stronger sense of place value, since you have to think about how many tens and ones make up a number before you can name it. This same thinking about groups of numbers shows up again when telling even numbers from odd numbers, so it is worth strengthening alongside skills such as identifying a number as even or odd.

Related lessons

Math 1