You can treat the negative like it is a negative one that is being multiplied by the fraction.
For example....
\(-\,\frac58=(-1)\,*\,(\frac58)\)
Then...just divide the fraction inside the parenthesees like normal.
\((-1)\,*\,(\frac58)=(-1)\,*\,(0.625)\)
And multiplying the negative one makes it
\((-1)\,*\,(0.625)=-0.625\)
Do you have a specific problem you need help on?