Fuel calculation

Hello trying to calculate fuel without device sensor. I am choosing
Fuel
9999999 - 5.5 * totalDistance / 100000
number
The average consumption is 5,5 liters per 100 km. But in reports I am getting this error.
class java.lang.String cannot be cast to class java.lang.Number (java.lang.String and java.lang.Number are in module java.base of loader 'bootstrap')
What can be wrong?

It looks like somehow the result of your expression is a string. Can you please provide screenshots of all expressions you have.

Yes this is the expression.
https://drive.google.com/file/d/1WSZEKldECReXmEHPLbPE1wbgSZwsIr2I/view?usp=sharing
It is a custom UI but this is not the issue

It is a custom UI but this is not the issue

And what makes you think that? Please provide a screenshot from the database then.

https://drive.google.com/file/d/1ss5GH3x-3PWJV5p88L2bCKOPAOMwdB8U/view?usp=sharing
This is the database.
I am assuming that because several other attributes are working

The attribute is generating a responce like this
Fuel 9997954.7 l Can it be the decimal? , instead of . ?

What do you get in the API response?

{"id":36,"description":"Fuel 5,5 lt/100km","attribute":"fuel","expression":"9999999 - 5.5 * totalDistance / 100000\n","type":"Number"}

I see multiple issues that are clearly caused by your custom app.

Please can you tell me ?