Hi there,
Assuming only one value can be empty and 0 is considered empty, I would solve the problem with a microflow looking like this:
The loop calculates the value of all C values (from the (C1 * C2*...) in your formula
Each decision checks if one of the values is empty and rearranges the calculation to calculate the empty value:
Alternatively - if you don't want to assume 0 is an empty value, since you're using Mendix 10.16, you can pass in a string parameter when calling the microflow via a button.
However, this would mean you would need a separate button for each value you wish to calculate:
Hope this helps,
Liam