Writing Numbers 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.

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.

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.

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.

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.

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.

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.

• 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.

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