77.5*0.48+4.8*2.25
=77.5×0.48+0.48×22.5
=0.48×（77.5+22.5）
=0.48×100
=48
6分之5*0.25+4分之1*6分之1
=(5/6)×0.25+0.25×(1/6)
=0.25×[(1/6)+(5/6)]
=0.25×1
=0.25