1.8x2.6+7.5x1.8-1.8=1.8x(2.6+7.5-1)=1.8x9+1.8x0.1=16.2+0.18=16.38
1.8X(2.6+7.5-1)=1.8X9.1=1.8x(9+0.1)=1.8x9+1.8x0.1=16.2+0.18=16.38