(1)(-10)+15=5;
(2)(-0.9)+(-3.6)=-4.5;
(3)0+(-4.5)=-4.5;
(4)15-(-7)=15+7=22;
(5)(-2.7)-(+2.3)=-2.7-2.3=-5;
(6)-=;
(7)18+(-12)+(-21)+(+12)=18-12-21+12=18-21=-3;
(8)0.35+(-0.6)+0.25+(-5.4)=0.6-6=-5.4;
(9)-26+43-24+13-46=-96+56=-40;
(10)(-3)+12.5+(-16)+(-2.5)=-20+10=-10. |