Calculating Remaining Amount by subtracting item from each previous responses

[kmno_2020]

I have Opening Balance. When I record number of item, I would like to display remaining Balance by subtracting from opening balance. For example, I have 300 apple to sell. If I sell 30 apples today, I want to calculate Remaining balance is 270. Next day, I sell 25 apples, The Remaining Balance is 245. In form, I want to display remaining balance. Please solve my problem.

[hakan_cetinkaya]

Hi @kmno_2020, welcome back.

If I understand your question correctly, this is how to solve it:

@kmno_2020

For example, I have 300 apple to sell. If I sell 30 apples today, I want to calculate Remaining balance is 270.

It seems you need to use calculate question for the first part:

https://support.kobotoolbox.org/calculate_questions.html

@kmno_2020

Next day, I sell 25 apples, The Remaining Balance is 245. In form, I want to display remaining balance

And for this issue I think you can use dynamic data attachment:
https://support.kobotoolbox.org/dynamic_data_attachment.html

If you need further help, let the community know.
Best,