To add these numbers together, we first need to convert all the mixed numbers to improper fractions:

-8 4/9 = -8 + 4/9 = -71/9
2 7/18 = 2 + 7/18 = 43/18

Now we can add all the fractions together:

-71/9 + (-12.15) + (-0.05) + 43/18

To add fractions, we need to find a common denominator. In this case, the lowest common multiple of 9 and 18 is 18.

-71/9 = -71 * 2 / 18 = -142/18
43/18 remains the same

Now the expression becomes:

-142/18 + (-12.15) + (-0.05) + 43/18

-142/18 + (-12.15) + (-0.05) + 43/18 = -142/18 - 12.15 - 0.05 + 43/18
= (-142 - 12.15 - 0.05 + 43)/18
= (-154.20 + 43)/18
= -111.20/18
= -111.2/18
= -111 1/5

Therefore, -8 4/9 + (-12.15) + (-0.05) + 2 7/18 = -111 1/5