(15.6+9.744/2.4)*0.5 2.881/0.43-3.5*0.24 13.5*0.68/8.543.6-7.6*4.1(86.9+667.6)/50.3(73.5+80.5)/(10+12)(7.8*15+5.1*10+6*5)/(15+10+5)12.53-1.35*2-9.318*(4-3.75)/0.16-1.3*(10-7.3)75÷〔138÷（100-54）〕 ...