Is it possible to do an addition in an Action button ?

Hello community,

Context of my project :

Fitness app where an user can fill a form with calories, proteins, carbs... And then those informations are stored in my firebase collection where I've an collection for each categories.

Then I've an dashboard where I display those data.

My issue :

My calories collection --> current_calories (double), total_calories (double)

I want when the user click on the button add calories to update the current calories

eg : 0 calories then the user add 1000 calories in the form then the current calories is equal to 1000.

For now my action button is an UPDATE of the current_calories but the issue is that the 2nd time the user fill the calories form, It will erase the 1000 to replace it with the new value.

I want to additionate the current_calories with the 2nd value.

Is it possible ?