Try using Windows calculator for up to 32 digits of accuracy. Format cells as
text then enter the values as text in Excel.

The following macro sums a selection of values in windows calculator and
copies the result to the clipboard. To enter the answer in a cell, format a
cell as text and then choose Edit Paste.

Sub SumValsWithCalc()

Dim ReturnValue, I
ReturnValue = Shell("CALC.EXE", 1) ' Run Calculator.
AppActivate ReturnValue ' Activate the Calculator.
For Each I In Selection
SendKeys I & "{+}", True ' Send keystrokes to Calculator
Next I ' to add each value of I.
SendKeys "^C%{F4}", True ' Send ALT+F4 to close Calculator.

End Sub


"mohammad" wrote:

how can I sum up the values with more than 15 significant digits?