If this is a simple debit/credit problem, here is one of the way to solve. I have tried creating a sample table called "Account".

create table Account(id int identity, F1 int, F2 int,F3 int)

insert into Account(F1,F2)

values

(20000,0),

(0,5000),

(55000,0),

(0,60000),

(0,20000),

(11000,0)

select id,F1,F2,(select SUM(F1-f2) from Account where id <=a.id) F3 from Account a