How do I auto-adjust numbering in tables in Pages?

I have a checklist table with the first column being a numbered list of tasks, and the subsequent rows indicating how far I have got along the path to finish each task.

I want to add other tasks to the list but the numbers in the column don't automatically adjust to allow the new tasks to fit in with the number sequence. There doesn't seem to be any way of formatting the cell so that keeps numbering in sequence as I add new tasks.

Please can you help me?

[Re-Titled by Moderator]