41.2x8.1+11x1.25+53.7x1.9
1个回答

原式=41.2*8.1+11*1.25+(41.2+12.5)*1.9

=41.2*8.1+41.2*1.9+11*1.25+1.25*19

=(8.1+1.9)*41.2+(11+19)*1.25

=10*41.2+30*1.25

=412+37.5

=449.5