1. The problem is to find the sum of $-8$ and $-27$. 2. We use the rule for adding integers with the same sign: add their absolute values and keep the common sign. 3. Calculate the absolute values: $|{-8}| = 8$ and $|{-27}| = 27$. 4. Add the absolute values: $8 + 27 = 35$. 5. Since both numbers are negative, the result is negative: $-35$. 6. Therefore, $-8 + (-27) = -35$.