8+(-9)+(-7);-3+(-4)+(-5)+(-6);-4+8+(-9)+3;8+(-10)+(-12)+3;

8-9-7= -1-7= -8-3-4-5-6= -7-5-6= -12-6= -18-4+8-9+3= 4-9+3= -5+3= -28-10-12+3= -2-12+3= -14+3= -11