Answer
$-1$
Work Step by Step
In adding two numbers with the same sign, perform the following steps:
(1) Add their absolute values.
$|-\frac{7}{8}| + |-\frac{1}{8}| = \frac{7}{8} + \frac{1}{8} = \frac{8}{8}=1$
(2) The sum must have sign common to the addends.
$-\frac{7}{8}+(-\frac{1}{8}) = -1$
Thus, the sum is $-1$.
