(1):(-8)-(-15)+(-9)-(-12) =-8+15-9+12 =10 (2):(-40)+29-(-15)-|-24| =-21+15-24 =-30 (3):(2/3)-(1/8)-(-1/3)+(-3/8) =（2/3)-(-1/3)-（（1/8）-（3/8)） =1+(1/4) =5/4 (4):0.5+(-1/4)-(-2.75)+(1/2) =0.5+（1/2...