How can I convert text representations of numbers into Excel numbers, especially negative values? For example, the string "9,669.34" (without quotes) should become the number 9,669.34 and the string "2,553.57-" (again, without quotes) should become the number (2,553.57).
When I used the formula =SUBSTITUTE(A1,CHAR(160),"")+0, it worked well, but only for positive values. I received the result #VALUE! for all negative values.