Hi,
Add an empty column in the grid,
after that on row bound event use the following code,
protected void gridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
e.Row.Cells[10].Text = Convert.ToInt32(e.Row.Cells[8].Text) * Convert.ToInt32(e.Row.Cells[9].Text);
}
}</pre>