Writing Words as Numbers

Every number can be shown two ways: as a numeral, like \(47\), or spelled out in words, like "forty-seven." Writing words as numbers means reading a number word (or a few number words together) and writing down the matching numeral. This skill links reading with math, and it is the foundation for reading word problems, checking answers on worksheets, and understanding place value.

The numbers zero through twenty each have their own special word, and none of them follow a simple pattern, so they need to be learned by heart. Once these are familiar, every other number word is built from them.

After twenty, number words follow a clear pattern built from "tens" words: twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety. Each tens word gives the digit in the tens place, and any ones word joined to it with a hyphen gives the digit in the ones place. For example, "sixty-three" is built from "sixty" (6 tens, or 60) and "three" (3 ones), so \(60 + 3 = 63\).

1. Check whether the word is ten or under, or a teen word (eleven through nineteen); if so, write the matching numeral directly, since these do not split into separate tens and ones words.
2. Otherwise, listen for a tens word (twenty, thirty, forty, and so on) and write down its value.
3. Listen for a ones word (one through nine) joined to it and write that digit next to the tens digit.
4. Combine the two digits into a single two-digit numeral, remembering \(60 + 3 = 63\) works the same way for every tens and ones pair.

Example 1: Write "eighteen" as a numeral. Eighteen is a teen word, so it becomes \(18\).

Example 2: Write "seventy-two" as a numeral. "Seventy" gives 7 tens (\(70\)) and "two" gives 2 ones, so \(70 + 2 = 72\).

Example 3: Write "ninety" as a numeral. "Ninety" is a tens word by itself with no ones word attached, so it becomes \(90\).

• Mixing up teen words and tens words, such as writing 13 for "thirty" instead of 30.
• Forgetting the hyphen rule, since "forty-five" is one number, \(45\), written with two words.
• Reversing the digits, such as writing 54 instead of 45 for "forty-five."

Once converting words to numerals feels comfortable, practice spotting those numerals inside a hundred chart with missing values in a number grid up to 100, or build counting skills further with counting values in a number grid up to 100. It also helps to compare this word-to-numeral process with converting dot grids to numbers up to 100, another way of representing the same numbers.

Related lessons

• Math 1