化简四道计算题.

问题描述:

化简四道计算题.
6A+13A
6*-28-2.5*+30.5
8A-(5A+8)
(5A+7)-(4*+0.18)

6A+13A=(6+13)A=19A;
6*(-28)-2.5*(+30.5)=-168-76.25=0244.25;
8A-(5A+8)=8A-5A-8=(8-5)A-8=3A-8;
(5A+7)-4*(+0.18)=5A+7-0.72=5A+6.28.