-(8-x)-x=-8+x-x=-8
-----------------------------
(x-4)-(x+5)=x-4-x-5=-9
-----------------------------
-(y-a-3)-(4+a)=-y+a+3-4-a=-y-1
------------------------------
-(16-b+c)+(8+c)=-16+b-c+8+c=-8+b
-----------------------------
1.20+12=32
32÷4=8
2.20÷4+12÷4=5+3=8