@Polly: Assuming your data are in the first sheet of an xls file, you have a header row and two columns A and B which will have to be added in your program, then this is the way to get you started (no guarantee, did not run it...):
type
TDataRec = record ColAValue, ColBValue, SumValue: Double; end;
var
data: array of TDataRec;
workbook: TsWorkbook;
worksheet: TsWorksheet;
row, lastrow: Integer;
begin
workbook := TsWorkbook.Create;
try
workbook.ReadFromFile(AFileName, sfExcel8);
// assuming an Excel8 file, but you can drop this parameter, but you must be aware of some
// exceptions in the debugger then, they don't occur without the debugger.
worksheet := workbook.GetWorksheetByIndex(0); // 1st worksheet
lastrow := worksheet.GetLastRowIndex;
SetLength(data, lastrow); // normally: "lastrow+1", but we drop the first row!
for row:=1 to lastrow do begin // we skip the first row because of the headers!
data[row].ColAValue := worksheet.ReadAsNumber(row, 0);
data[row].ColBValue := worksheet.ReadAsNumber(row, 1);
data[row].SumValue := data[row].ColAValue + data[row].ColBValue;
end;
finally
workbook.Free;
end;