(-13)+29+(-9)+13= -13+29-9+13=20
(-3)+(-28)+27+7= -3-28+27+7= -31+34=3
-5+(5+(-99))=-5+(5-99)=-5+5-99= -99
(-48+91)+(-91)= -48+91-91= -48
(-34+59)+34= -34+59+34 =59
(47+(-91))+91= 47- 91+91= 47
(-4)+(-2)+22+14= -4-2+22+14= -6+36= 30
-28+(18+29)= -28+47 = 19
-10+(-10+30)= -10-10+30= -20+30=10