Hi @SerrePipe 

Check this help article: https://support.google.com/docs/answer/56470?hl=en&co=GENIE.Platform%3DDesktop

Hello @SerrePipe and welcome to the Community! :)

This type of issue, where the format changes, can occur if the format we’re sending to Google Sheets is different to the format within the spreadsheet. ​​

You mentioned that even after you change the format in Google Sheets it still stays as text and not a number. When you changed the format did you select the entire column of cells or just the ones that already had a value in them?

If it was just cells with an existing value in them that were selected, then any subsequent rows that were added would have continued to have the previous text format, as they would not have had their format settings changed. Do you think that might have been the case here?

Thank you all for your answers. 

@SamB I’ve tried both, I’ve selected the entire column and also just the cell, both case number stay as text. So i cant do any addition or multipication with them..

Any other clue ?

Thank you again for your help

@SerrePipe 

A possible workaround is to use a different app such as Airtable: https://zapier.com/apps/airtable/integrations#triggers-and-actions

Airtable is a relational database and has defined field formats. (e.g. Number: https://support.airtable.com/hc/en-us/articles/360021586274-Number-field-type)

I’ve resolve partially my problem by making a mirror of the column. In the copy, numbers appears normally and I can addition them.