Is it necessary to put a numeral in parentheses after you have already written the number in words?

Example: We will need two (2) chairs.
Conversely, is it necessary to write the number in words after you have already used the numeral?
Example: We will need 200 (two hundred) chairs.
If your document is dense, has a lot of numbers, or contains large numbers, the numerical form helps your readers scan information quickly. Conversely, while we may make a typo with only a numeral, we are almost guaranteed accuracy by writing the number in word format. So using a combination of numerals and written number format can be useful without being redundant.


Thanks for this valuable information Jane!