I'm trying to do the following:

I have a currency value in B1. I want to subtract a value each month (B1-C1, B1-D1, etc.) and update the value in B1 with the new result so that it becomes available for the following month's entry (B1-E1).

This would be similar to a budget problem where B1 is the outstanding balance and each month's payment is subtracted from the balance updating the outstanding amount. Is this possible?

A newbi,
AF1HS