Numbers :



If your writing contains numbers, the general rule is to spell out in letters all the numbers from zero to nine and use numerals for larger numbers; but there are exceptions.


If what you’re writing is full of numbers and you’re doing math with them, stick with numerals.


Approximations like “about thirty days ago” and catch-phrases like “his first thousand days” are spelled out. Large round numbers are often rendered thus:


“50 billion sold.”


With measurements, use numerals:


“4 inches long.”


Never start a sentence with a numeral.


Either spell out the number involved or rearrange the sentence to move the number to a later position.