If I am using the form calculation widget, alongside the matrix dynamiq

If I am using the form calculation widget, alongside the matrix dynamique how do I make sure it only calculates one column of the matrix.

It is not possible to perform calculation with dynamic fields, such as Matrix Dynamique, Configurable List or Infinite List widgets. 

Instead of Matrix Dynamique, maybe you ca use Spreadsheet widget or Input Table (Matrix) field. 

How to Perform Form Calculation in the Matrix Field?

Let us know if you need further assistance. 

It does work with the table I have inserted but is it possible to use form calculation on a table where the user can add as many rows as is needed. At the moment one has to sacrifice either the ability to calculate all the values or the ability to dynamically add rows to the table.

It is not possible to use from calculation with dynamic fields (fields where your users can add as many rows as is needed). We can raise this request to our developers. Just tell us with which dynamic field you want to perform form calculation. Is it with Matrix Dynamique widget?

For now I can only suggest you to increase the number of rows inside of your Input table. Your users can fill as many rows as is needed.