I'm creating a datatable (see below) that is going through each row of my
dataset and add new rows per each column created. Is there a way to store
the GrossSales figures so I can use
those numbers in for a calculation within the Expenses row?

My data for the dsSales dataset like this:

year       totalGross         SalesmanLastName
2005         45,000             Smith
2004         25,000              Jensen
2003         12,000            A. Smith

My data for dsExpenses is coming out like this:
year       Expense         SalesmanLastName
2005         4,000             Smith
2004         1500              Jensen
2003         12,000            A. Smith

is there a way to store the TotalGross and use that for a calculation within
the foreach {} loop for the dsExpense so I can have the net calculated? I
have to seperate dataset due to the data is coming from 2 seperate tables
within the database

public DataTable Results()
{
     dtFigures = new DataTable();
     dsSales = GetSalesValues();

      foreach (DataTable dt in dsSales.Tables)
       {
            foreach (DataRow dr in dt.Rows)
            {
                dr = dtFigures.NewRow();
                dr["SubHeader"] = "Sales Figures"
                dr["Year"] = dr["Year"].ToString();
                dtFigures.Rows.Add(dr);

                dr = dtFigures.NewRow();
                GrossSales = Convert.ToDecimal(dr["totalGross"]) / 1000;

                dr["MetricType"] = "Gross Sales
                dr["Year"] = dr["Year"].ToString();
                dr["Year One"] =
Convert.ToInt32(GrossSales).ToString("c0");
               dtFigures.Rows.Add(dr);
         }
    }

       dsExpenses = AllExpenses();
       foreach (DataTable dt in dsExpenses.Tables)
       {
            foreach (DataRow dr in dt.Rows)
            {
                dr = dtFigures.NewRow();
                dr["SubHeader"] = "Expenses";
                dr["Year"] = dr["Year"].ToString();
                dtFigures.Rows.Add(dr);

                dr = dtFigures.NewRow();
                dr["MetricType"] = "Year to date expenses";
                dr["Year"] = dr["Year"].ToString();
                dr["Year One Expenses"] = Convert.ToDecimal(dr["Expense"])
/ 1000;
               dtFigures.Rows.Add(dr);
         }
    }
}