Precision as Displayed

using (var p = new ExcelPackage())
{
    var ws = p.Workbook.Worksheets.Add("Sheet1");
    ws.Cells["A1"].Value = 123.456789;
    ws.Cells["A2"].Value = 987.654321;
    ws.Cells["A3"].Formula = "SUM(A1:A2)";
    ws.Cells["A1:A3"].Style.Numberformat.Format = "#,##0.00";
    p.Workbook.FullPrecision = false;  //This will round the values in A1 and A2 according to the number format "#,##0.00". 
    //Any changes to cells will also be rounded depending on the number format.

    ws.Calculate(); //Calculation results will also be rounded in the sane way.

    //Now the values in A1:A3 will be:
    Assert.AreEqual(123.46, ws.Cells["A1"].Value);
    Assert.AreEqual(987.65, ws.Cells["A2"].Value);
    Assert.AreEqual(1111.11D, ws.Cells["A3"].Value);
}