Q. If numbers must be written out by using words, are commas added in the same places as they would be used for digits? Example: 23,504,070; twenty-three million, five hundred four thousand, seventy. Thanks!

A. No commas should be used when numbers are written out:

103,000 = one hundred three thousand

The longer the number, the more awkward it may seem, but commas would make the number look like a series of smaller numbers, something that doesn’t happen with numerals because there are no spaces, for one thing.