We want to know how many brownmies did Fred and his family eat together.
We will call to the total of the brownies by 1. On this case, after Fred ate 1/3 of the brownies, he will have:

This means that he has left 2/3 of the brownies. After his family ate 1/6 of the brownies:

This means they will have left 1/2 of the tray of brownies, and that they ate half of it.
Y is same as the missing angle, the triangle need to equal to 180 so if you add 20 to 60 it equal to 80
use 180 to subtract to 80 you will get the missing x, x=80
3-6+12=9
Steps
you have to add first so you must add -6+12 which will be -6
Then you will take 3 - - 6 which will make it 9
No it doesn’t. This is because if you have a negative number and multiply it by itself 3 times, you’ll still have a negative number (-1 times -1 times -1 is still -1). On the other hand, if you take a negative number and multiply it by itself twice (-1 times -1) you’ll have the answer that is positive (1).