Problem:

Column A contains an imported list of positive and negative numbers.
For negative numbers, the minus sign appears to the right, rather than to the left.
We want to convert all the numbers with trailing minus signs to normally-signed negative numbers.

Solution:

1. Use the RIGHT and SUBSTITUTE functions as shown in the following formula in column B:
=IF(RIGHT(A2,1)=\"-\",SUBSTITUTE(A2,\"-\",\"\")*-1,A2)
2. Use the VALUE, IF, RIGHT, LEFT, and LEN functions as shown in the following formula in column C:
=VALUE(IF(RIGHT(A2,1)=\"-\",RIGHT(A2,1)&LEFT(A2,LEN(A2)-1),A2))