acumulative sum with ireport

[jhon masco]

Hi everybody
I need to do a sum acumulative in a column of my report. I retrieve a value from the database and I fill the other columns with some mathematical operation with this value.
The last column must be the sum and in every row it must to sum the above value also: For example;

  DATA-DB    | COLUMN_1 (A)       |    COLUMN_2 (B)       |       COLUMN-3 (C)         |         COLUMN-4 (D)         | 
      2000   |     (2000/2)       |   (2000 *60)/365     |     column_1 + column_2     |    column_1 + column_2     |      D1
      1500   |      (1500/2)      |    (1500*60)/365     |     column_1 + column_2     |    column_1 + column_2 +D1 |      D2
      3000   |      (3000/2)      |    (3000*60)/365     |     column_1 + column_2     |    column_1 + column_2 +D2 |      D3
         *                 *                           *                                    *                                           *        
         *                 *                           *                                    *                                           *     

How Can i do that? I dont find the way. I had tried some variablesand things similar to : $V{var1}= $V{var1}+$V{TOC} and i get errors.!
I using Ireport 4.0.
Please let me know if that is possible in ireport?
Thanks

[jhon masco]

I solved the problem!!! Thanks...

[Nitesh Kant]

jhon masco wrote: I solved the problem!!! Thanks...

It will be great if you can also give us the solution.

[jhon masco]

It will be great if you can also give us the solution

You are right sorry!

Note: my main language is not english and I dont live there, therefore i will try to write everything correctly
Here the solution:
create a variable for each operation or formula, is to say:
Variable1 = (2000/2) or (DATADB/2)
Variable2 = (2000 *60)/365 or ((DATADB*60)/365)
Variable3 = (Variable1 + Variable2)
Variable4 = (Variable3)

them in the Variable4 properties set:
Variable Class = java.lang.double
Calculation = Sum
Reset Type = Column or Page or Report (depend you case)
Increment type = Group
Increment Group = (choose the group that you created before, when you use the wizard for example you create a group)
Variable Expression = ($P{Variable3}>0) ? $P{Variable3}: 0

And ready, that is all.
Any doubt let me know
Suerte