How To Work With DataGridView Control Events and also performing mathametical operations in Wcf ?

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C#

In That Data Grid view Ex: i am having Format Like Columns Particulars,Open Issue, Total,Return,Sale Amount Finally Add.
In Those columns user only enters the data in sale and issue then total will be appeared(total=open+issue) in total column cell when issue column cell textchanged.
When user enters the return then sale wil be displayed in sale column cell like (sale=Issue-Return);
The amount Will be displayed in Amount Column That is like (Amt=Sale*Particlurs)In Particulars i want ComboBox in that values are ex:10,154,96,16...
Finally Add Column Cell (+)Button will apear and when user clicks the button then next row will be created this is my format.. Will you people please help to me give an answer to my paricular format please sirs/ madams....

Thanking You ....
Ekambharam.p