To sum these fractions, we can follow using the next steps:
[tex]-\frac{5}{8}+\frac{1}{8}=\frac{-5+1}{8}=\frac{-4}{8}=-\frac{2}{4}=-\frac{1}{2}[/tex]The error was in adding the numerator in the third step. The algebraical sum of -5+1 is -4 (not -6). After that, the result is -4/8. We simplify the fraction (dividing by 2) until we have an irreducible fraction (-1/2).