Answer
$0.875$
Work Step by Step
If we can write a fraction so that its denominator is one of 10,100, 1000,...,
we can easily write it as a decimal number
The denominator is 8, and $\quad 8=2\cdot 2\cdot 2$,
so, if we multiply each of the factors with a 5, we would get that
$8\cdot 5\cdot 5\cdot 5=10\cdot 10\cdot 10=1000,$
Using the fact that $8\cdot 125=1000,$
$\displaystyle \frac{7}{8}=\frac{7\cdot 125}{8\cdot 125}=\frac{875}{1000 }$
We write this as a decimal number with three digits after the decimal point:
$= 0.875$