Hi all. I have an app to record my department's fund. There's a column namely "AmountPaid". For any payments by the staff, I will record the info/data into the column.

My question is, I want to get the total sum for "AmountPaid", and next to get total sum for "Expenses". My aim is to get [AmountPaid - Expenses] to obtain their nett balance.
For the expenses, do I need to create a new sharepoint list just to record the expenses? As of now, I still haven't created any column to insert data for Expenses.
Thank you so much!