41.2x8.1+1又4分之1+53.7x1.9=41.2x(10-1.9)+1.25+53.7x1.9=41.2x10-41.2x1.9+53.7x1.9+1.25=41.2x10+(53.7-41.2)x1.9+1.25=412+12.5x1.9+12.5x0.1=412+12.5x(1.9+0.1)=412+25=437