How can you find the sum [8 + (-4) ] + (-8 + 4) using mental math?

For the first brackets, You can subtract 4 from 8 and that makes 4. For the second bracket, you can add - 8 and 4 which gets you 4. You have simplified what is inside the brackets, now you can add them together. 4 and 4 equals 8. So the answer is 8. You can figure it out other ways also