A writer spells out a number by using the English word for the number instead of the numeral. Some numbers have a phonetic spelling, such as "three" or "ten." Other numbers require memorization of the spelling, such as "two" or "eight."
Numbers above 20 may use a hyphen, such as "thirty-four" or "fifty-five." An example of the spelling of a three-digit number is "one hundred forty-four." An example of a four-digit number is "one thousand five hundred ninety-seven."
In some situations, writers typically spell out numbers rather than use numerals. Some of these situations include numbers less than 10, at the beginning of a sentence, in fractions and in time references.