Final answer:
To find the sum of the given expressions, we subtract the smaller number from the larger number and use the sign of the larger number. Therefore, [3 - 8] + [4 - 5 - 6] = -12.
Step-by-step explanation:
To find the sum of the given expressions, we need to add the corresponding terms together. When adding numbers with different signs, we subtract the smaller number from the larger number and use the sign of the larger number. So, [3 - 8] + [4 - 5 - 6] = [3 + (-8)] + [4 + (-5) + (-6)] = -5 + (-7) = -12.