Dynamic form ana automatic sum and average

Hello

I would like to create a form where the user can add rows in a table, and after completing the data table, it will be automatically added up and be counted average.

Analysing the examples I was able to make a dynamic form but I can not add automatic counting.

I would also like to add the following lines after the automatically appear in the line number in the first column.

Proszę o pomoc dla mnie jeśli możecie

Here is my example project

I warmly greet

Mario