C# .NET - CR Formula

My requirement is that in Crystal Report I'am displaying a value say(25000) in page header(This value may vary.)

In details Section

In the first row i want to display the value in the page header+some other value(25000+5000=30000)  in the first row
In the` second row i want to display the value in the first row (30000+some other value).

How i can write the formula for this

Hello,

how u are assigning the data to crystal table?
i think if u are having data table then in that table it self u can write the logic in such way that it carries the value of previous row and add it into next row.

something like this

select a.somcolmn1, a.somcolmn2, sum(b.somcolmn) as price
from TableName a cross join Sametable b
where b.Id <= a.Id
group by a.Id, a.somecolmn

then assign the entire table to crystal row

Thanks
D