First, find 1/7 as a decimal by dividing 1 by 7:
$${\frac{{\mathtt{1}}}{{\mathtt{7}}}} = {\mathtt{0.142\: \!857\: \!142\: \!857\: \!142\: \!9}}$$
Then, add that to 1:$${\mathtt{1}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{1}}}{{\mathtt{7}}}} = {\frac{{\mathtt{8}}}{{\mathtt{7}}}} = {\mathtt{1.142\: \!857\: \!142\: \!857\: \!142\: \!9}}$$
Finally, since this is all negative, add a negative sign in front of the number:
- 1.1428571428571429
Rounded:
-1.143