UDF to perform calculations with big numbers _BigNum_Parse _BigNum_Add _BigNum_Sub _BigNum_Mul _BigNum_Div _BigNum_Pow _BigNum_SQRT _BigNum_n_Root _BigNum_Mod _BigNum_Round _BigNum_Compare EDIT: updated BigNum.au3 BigNum_example.au3 #include "BigNum.au3" $X = "10000000000000000000" $Y = "0.000000000000000001" MsgBox(0, "Addition", $X & " + " & $Y & " = " & _BigNum_Add($X, $Y)) $X = "-10000000000000000000" $Y = "10000000000000000000" MsgBox(