Do you use digits instead of words?
Whenever writing numbers for a web audience, it's generally a good idea to use numerals, especially for complicated numbers. Numerals are more easily noticed when a page is scanned by a user's eye. For example:
There are seventy three good reasons to do this.
Figure: Bad Example - The number is spelled out.
There are 73 good reasons to do this.
Figure: Good Example - This is easy to read and more noticeable