In this article
Calculating a Value from Table Cell Values using a Basic Formula:
var x = report.TableUtils.GetCellValue("AgeandGender", 1,1).Value; //tableID, rowID, ColID
var y = report.TableUtils.GetCellValue("AgeandGender", 2,1).Value;
var z = report.TableUtils.GetCellValue("AgeandGender", 3,1).Value;
var sum = (x + y + z)*100;
var newValue: String = sum.toString();
newValue = newValue.Substring(0,2);//remove trailing numbers
newValue += " %";
text.Output.Append(newValue);