My Page/Post has a number in the URL

WordPress appends a number to the slug when the database already contains a duplicate slug. It will append the number when the duplicate post or page has been moved to the trash. When Pages or Posts are “deleted” they are simply moved to a Trash folder. Items within your Trash folders can be restored or permanently deleted within 30 days of their original trashing. This is specially useful if you need to retrieve a Page or Post within those 30 days, or if you accidentally deleted an item. If you create a Page or a Post with the same name as a deleted one, WordPress will append a number to it since one already exists in the database. This may not look that nice in the permalinks.

The Fix:

Simply access the Trash Folder for Pages or for Posts and “Permanently Delete” the item before creating a new one. For more info on WordPress Trash, please see the following: