原式=53.5*(35.5+43.5)+78.5*46.5
=53.5*78.8+78.5*46.5
=78.5*(53.5+46.5)+0.3*53.5
=78.5*100+16.05
=7850+16.05
=7866.05
题目错了,应该是53.5*35.5+53.5*43.2+78.8*46.5