Calculate amount

[Stefaan_EEMAN]

Hello,

message edited below...

I need a formula to calculate amount from previous row column A  + this row column B in this row column C this row column B. For example.... Colomn A from previous row (row 4) is 3000, I have to calculate  (row5) column B is 1000 so in this row column C should be 4000.

i correct this explanation...

the column [new amount] from previous row should be added up with column [ amount] in this row.

SO..... row 4 [new amount] is 3000 and this row (row 5) column [amount] is 1000 then colomn [new amount] this row (row 5) should be 4000.

Thx for the help.