With this WordPress Snippet you can add a Numerical Number to your WordPress Posts or Custom Posts. In this implementation we are creating a custom WordPress Loop and adding a sequential post number  1, 2, 3, 4 etc above the post title:-

The numbering comes from the PHP variable '$postNumber' and is automatically incremented on a post by post basis / loop. Note in this case we are using a Custom Post Type so either replace 'your_post_type' or to use standard Posts then just add in 'post'.