2.5×(8+0.4)=2.5x8+2.5x0.4=20+1=216.4+3.6×1.5=6.4+3.6x5x0.3=6.4+18x0.3=6.4+5.4=11.835-35×0.7=35x(1-0.7)=35x0.3=10.5